Intel DP55KG "Kingsberg" Mainboard: Extreme King of the Hill?

Can anyone know better than CPU and chipset developers themselves how a mainboard should work? Today we are going to talk about a “reference” LGA1156 ATX mainboard from Intel that belongs to the Extreme series.

by Doors4ever
12/02/2009 | 04:11 PM

The list of LGA1156 mainboards on the new Intel P55 Express chipset we have tested so far has grown pretty long already. It includes ASRock P55 Deluxe, Asus P7P55D Deluxe, Biostar TPower I55, DFI LANPARTY DK P55-T3eH9, Gigabyte GA-P55-UD6 and GA-P55-UD3R. We are going to test more solutions from these manufacturers in the future as well as introduce new names to you, however, we are still missing one single thing. Who could know better than the CPU and chipset developer what a proper mainboard should be like? Therefore, we have been looking forward to the opportunity to test a solution from Intel for a while. At this time the company has four LGA1156 products on Intel P55 Express chipset: two regular boards from the Media Series and two boards from Extreme Series. Regular boards are the full-size Intel DP55WG and microATX Intel DP55WB. The Extreme Series lineup includes a microATX Intel DP55SB board as well as an ATX solution - Intel DP55KG, which we are going to discuss today.

Package and Accessories


Intel mainboards from the Extreme Series use a human skull as an emblem and Intel DP55KG solution is no exception in this respect. In fact, it is pretty interesting, why this serious company decided to choose a not serious symbol like that. Of course, had it been a dog’s or chicken’s skull, we would definitely have much more questions, but I have to admit that it is still a little weird to see this image on boards and boxes.

The back of the Intel DP55KG box shows what it looks like, lists the board’s features and peculiarities:

Intel mainboards have always come with scarce accessories. This time again we get a pile of marketing materials instead of a normal user manual. However, the board comes with a colorful multi-lingual poster with assembly and installation instructions, so you shouldn’t have any problems in the beginning. And then you can always download the electronic version of the manual and check it out. As for the peculiarities of the mainboard accessories bundle, I could mention a bridge for connecting two graphics cards together. Note that the board supports not only ATI CrossFire but also Nvidia SLI configurations. Another unusual component is a cable antenna, because this board boasts a pretty rare feature – an integrated Bluetooth controller.

Design and Functionality

Only at first glance you may think that Intel DP55KG mainboard is designed following the classical traditions. In reality it has a number of special peculiarities. For example, Intel DP55KG PCB surface is all covered in numerous components and contact tracks, like all other mainboards. However, this normal looks continues only up to the line going through the first top PCI connector. After that we‘ve got a lot of empty space. Pretty strange, isn’t it?

At this point I would like to recall that Intel has four LGA1156 mainboards in their lineup based on Intel P55 Express chipset. However, Intel DP55KG is built not after a full-size Intel DP55WG, but after a microATX Intel DP55SB, which also belongs to Extreme series. Just look at the photo of the small DP55SB and will immediately notice amazing similarity between it and our today’s hero.

Usually when we talk about microATX mainboards we point out their differences from the full-size ATX solutions by listing the things that had to be sacrificed for the sake of smaller more compact size. This time things seem to be a bit different. We get the impression that they didn’t cut down Intel DP55KG mainboard to become a microATX modification, but used Intel DP55SB as a basis for designing the full-size DP55KG that is why we have all that empty space on the PCB, which had to be filled with something. The primary difference between the ATX and microATX board is obviously larger number of expansion slots: besides two graphics card slots and two PCI Express 2.0 x1 slots, they also added two regular PCI and one PCI Express 2.0 x4 slot.

Like many other mainboards on Intel P55 Express chipset, only the first PCI Express 2.0 x16 connector on Intel DP55KG can actually work at its full speed. If we install two graphics cards, the speed is reduced by half. In this case, Gigabyte would only lay out half of connector contacts inside the second PCI Express x16 slot, because the second half won’t ever be used anyway. Intel takes a different approach: the second graphics card slot is an almost common PCI Express x8, while the third one – PCI Express x4. The difference is the use of connectors with open back sides and the graphics card retention at a little distance. Another peculiarity is the implementation of additional power supply for graphics accelerators: they use a power connector similar to those for SATA devices instead of a common large four-pin or small four-pin connector, like the one used for floppy disk drives.

On the other side of the PCB we see six Serial ATA ports provided by the chipset and two additional SATA ports implemented via Marvell 88SE6145 controller. The skull emblem this time serves more than just a decorative purpose. The outline of the skull will be highlighted blue and the eyes will blink red indicating HDD activity. It looks very attractive, but the skull took the spot originally occupied by the front panel contact and indicator connectors, which had to be moved higher up – they are not a little below the 24-pin power connector. The USB and IEEE1394 (FireWire) connectors are located there, too, which is very convenient for the front or top panel ports and very inconvenient for back panel ports. The POST code indicator also didn’t find a convenient location and had to move a little above the first PCI Express x16 graphics card slot. That is why you may have hard time taking the readings off of it, as it will be squeezed between the graphics card on one side and processor cooler on the other.

Note that the processor voltage regulator components have only two small aluminum heatsinks installed over them, which are fastened with regular plastic spring clips. Intel P55 Express chip is topped with a tiny aluminum heatsinks pressed securely with a steel bracket.

Almost the same heatsinks used to be installed over the chipset South Bridge chips. Just in case let me remind you that Intel DP55KG belongs to Extreme Series and boasts some overclocking functionality, but the CPU and chipset developer is still convinced that this simple cooling solution will be sufficient for any work modes. This once again proves that extremely complex chipset coolers with numerous massive heatsinks and heatpipes, which we have already seen on several LGA1156 mainboards, serve merely as customer appeal rather than cooling.

The back panel of Intel DP55KG mainboard carries the following ports and connectors:

Since the integrated Bluetooth controller uses one USB port, there remain 13 USB ports. Eight of them are on the mainboard back panel, four more exist as onboard pin-connectors and one more is an internal one. It is located between the processor socket and back panel ports and connectors, a little below the eight-pin processor power connector.

The components layout for Intel DP55KG mainboard shows a Power On button marked with the letter “V”. By the way, there is a large decorative white LED right next to it. It is turned off by default, but you can turn it on in the BIOS and adjust its brightness. It can also be switched to blinking mode, if necessary. As I have already said, the skull’s eyes indicate HDD activity. Besides, there are two LEDs that will light up in case CPU or its voltage regulator gets overheated (“P” and “Q”). The LED next to the 24-pin power supply connector indicates that the board receives power (“W”). You may have noticed that the board is free from all “obsolete” interfaces, such as PS/2 keyboard and mouse connectors, COM and LPT ports, IDE and FDD connectors.

Intel DP55KG mainboard has an integrated piezo-buzzer that beeps on every system star. There is no way to disable it, but the good thing is that it only beeps once instead of four, like on DFI LANPARTY DK P55-T3eH9 mainboard.

The table below sums up all technical specifications of the Intel DP55KG mainboard:

Overall, Intel DP55KG layout doesn’t get us raving. I also can’t say that we dislike it, but a few small drawbacks and inconveniences do spoil the impression. They have mostly appeared because the developers didn’t use the entire available PCB space. However, they did have an advantage over those makers who also had to find a place for IDE, FDD and sometimes even COM ports. It is highly likely that trying to save on development and production costs they took a microATX mainboard as a basis for their DP55KG solution. But although certain drawbacks could be justified for a microATX mainboard, we can’t overlook them in case of a full-size ATX solution, especially the top-tier flagship one. It must be ideal, but unfortunately, Intel DP55KG didn’t become that role model we’ve been looking for.

Supporting Documents

We already know that Intel mainboards never come with a printed manual, but there are two electronic versions available on their official web-site. One of them is called “Intel Desktop Board DP55KG Product Guide” and another one – “Intel Desktop Board DP55KG Technical Product Specification”. The difference between them is pretty obvious. The first one is targeted for end-users. It will explain how to install a CPU or replace the battery. The second one is intended for technical specialists. But the problem is that a lot of information is duplicated in both manuals, which I personally do not like, because I have to check out both of them to make sure that I don’t miss anything important.

Unfortunately, this time I noticed the whole bunch of errors and inconsistencies. For example, the manual for DP55SB mentions some non-existent blue SATA ports. There is a photo of this mainboard in the previous chapter of our today’s review, so you can try to find at least one port like that. Speaking of the today’s main hero, Intel DP55KG, the manual mentions HDD activity indicator and even points out its location. However, we already know that the skull’s eyes perform this function. In reality there is no LED where the manual points to.

However, Intel mainboard manuals do not contain only errors and inconsistencies, some things are explained way better than by other mainboard makers. I doubt that anyone will ever have problems installing two memory modules, even less so with four. But how do you install three memory modules, especially if they are of different capacity? Mainboard manuals would usually offer you complicated tables with different module combinations, which are pretty hard to figure out. Intel uses a much more illustrative approach: just look at the pictures and you will understand it right away.

So, each mainboard comes with two versions of the user manual. But the BIOS terms glossary is even harder to work with than these manuals. There are also two of those. The first one has all terms listed in alphabetical order, while the second – in order of appearance in the BIOS. Both glossaries refer to a few dozens of Intel mainboards that is why you have to look for the terms you need among a bunch of others that are not even relevant to your mainboard. Of course, it is way less convenient than a BIOS screenshot with immediate explanation of all parameters, which we see from other mainboard makers. However, this time the company has prepared a special document where all the info is presented in a more illustrative and traditional form. The document is called “Intel Desktop Board DP55KG and Intel Desktop Board DP55SB Extreme Series Performance Tuning Guide”. They use specific examples to explain how to set up your system for maximum performance, which parameters need to be adjusted, where they are located, what they are used for and how you could afterwards check the system stability. Very useful guide and I think you could read it even if you don’t own an Intel mainboard. All basic principles are the same, so they will be true for other mainboards as well.

Updating the BIOS

As always, before starting the tests we update the BIOS with the latest available version. Contemporary Intel mainboards offer at least four different ways of performing this procedure. You can find detailed instructions for all four of them on the company web-site and even watch a video demonstrating this process live.

If you use any of the Microsoft Windows OS, they recommend downloading an executable file that contains an extraction tool, updating utility and the actual BIOS file. After launching this file, all you need to do is agree to all terms. After that your system will reboot and the BIOS will be reflashed in the process. If you are using alternative operating systems, it would be best to download an image file and burn it on a CD disk and then reflash the BIOS from an optical drive. You can also use a boot-up flash drive: this approach will suit those users who would also like to adjust some BIOS settings, such as boot-up logo, for instance. Since the beginning of 2009 Intel mainboards acquired a built in utility for BIOS updating, which can be launched during mainboard start by pressing F7. In this case you just need to download the latest BIOS file and save it on any available storage medium: HDD, CD or DVD disk, or a flash drive.

In my opinion, the built-in utility is the most convenient tool for BIOS reflashing, but it is not the first time that Intel mainboards prepare a not very pleasant surprise for us here. This utility is missing in early BIOS versions. By the way, the early BIOS versions also do not offer the option of saving the user settings profiles. So, first time we had to update the BIOS from Windows, which is, in fact, the most frequently used updating method. Later on we confirmed that the built-in BIOS update tool does work correctly. Once you restart the system and press F7, you get access to the available drives list.

So, we are selecting the right device that contains a file with the new BIOS version. It is very nice the long file and folder names are allowed.

After that we just have to wait for the update to finish and restart the system.

During BIOS updating from Windows the last step will be exactly the same, but without any actions necessary on your part, just launch the executable file and agree to all terms.

BIOS Setup

At the time of tests the latest available BIOS version for Intel DP55KG mainboard was version from 10.28.2009. We reflashed it successfully and the first thing that came as a shocker to us was a total change of the color scheme. Instead of the familiar eye-friendly blue and gray interface, we got very contrasting and bright black and white one.

But not only the colors changed: the BIOS structures is also different now, some sections and sub-sections have been renamed or removed. These are definitely the changes for the best. Besides, the users will no longer risk getting confused by similar names of the two completely different sections – “Boot” and “Boot Configuration”.

At first let’s check the section that used to be called “Advanced”. Now it is called “Configuration” and contains a different set of sub-sections.

The first sub-section called “On-Board Devices” allows not only disabling sound and IEEE1394 (FireWire) controllers and configuring the USB, but also manage the onboard LEDs. Here you can also turn on the additional white LED, adjust its brightness, switch to blinking mode. You can also turn on blue lighting for the skull or turn off the HDD activity LEDs.

It is pretty funny, but looks like Intel software developers favor ASCII-art – drawing with symbols. You can see a schematic image of a skull on the right-hand side of the window, where you would normally get comments about the selected parameter. If you highlight the last parameter in the sub-section responsible for hard disk drives activity indication, then you will be offered to give the skull life:

These pictures may be not just entertaining but also useful. For example, if we go to the “PCI/PCIe Add-In Slots” sub-section of the “Configuration” section, we will see information about expansion cards accompanied with mainboard layout scheme on the right where the discussed connector will be highlighted.

To illustrate what I have just said, let’s move the cursor over the second graphics card slot and it will immediately light up on the layout on the right. The only thing I can’t understand is what’s so funny about the last PCI slot? Why is there a smiley face next to it?

However, before we get to the “PCI/PCIe Add-In Slots” sub-section we should actually check out a sub-section called “Fan Control & Real-Time Monitoring” from the “Configuration” section. Here we see very few options related to cooling fans:

All monitoring data have been moved to a separate page. It is not very convenient, but these data also aren’t too diverse, so the user will hardly go back to this section too often.

The next section has a very promising name – “Performance”. It welcomes us with a traditional warning about numerous dangers of messing with its contents.

Those who may not have the heart to proceed usually drop out at this point and only the bravest and most determined ones will be rewarded with a glimpse of a real “Performance” section.

Let me one more time point out that the BIOS settings in Intel mainboards are adjusted in a very inconvenient order. Suppose that we need to increase the base clock. On all other mainboards you simply have to select the appropriate parameter to start adjusting it.


However, this is not enough for Intel mainboards. you need to press “Enter” to change the color of your selection and only then you can in fact proceed to changing the parameter value.

Moreover, many mainboards allow entering the parameter value from the keyboard. With Intel mainboards you will need to go through the entire list of values until you scroll down to the one you need.

Some processor related parameters are located on a separate page called “Processor Overrides”.

“CPU Voltage Override Type” parameter allows you to choose between static and dynamic ways of increasing processor Vcore. In the first case the board will constantly support the voltage set using “CPU Voltage Override” parameter.  In the second case Intel processor power-saving technologies continue working; the Vcore will increase only under heavy load and lower in idle mode. “CPU Vreg Droop Control” parameter is intended to prevent the the processor core voltage from dropping under load.

The memory related parameters have also been moved to a separate page. Unfortunately, no improvements have been made in this section. Either all parameters are set automatically, or all are set manually. It is very inconvenient: many other mainboards can set the memory timings by themselves adjusting them for the memory frequency set by the user.

Moreover, the settings are not looped, which creates additional difficulties during their adjustment. For example, assume that I need to slightly increase the voltage on the memory controller integrated into the CPU. There is a special “Uncore Voltage Override” parameter for that. On most mainboards I would simply have to push the Up Arrow key twice to get to the right setting. On an Intel board I will have to push the Down Arrow key 14 (!) times to pass all other settings and get to the one I need.

The last “Bus Overrides” sub-section is not that interesting to talk about, so we won’t really go there this time.

As a result, all the changes we made will be quite correctly displayed in the “Performance” information field. It is very convenient that the first column shows the nominal values, the second – the desired changes and the third – the current settings that were used during system boot-up.

Everything is correct except the maximum processor clock frequency multiplier. In fact, no mainboard can display the processor clock multiplier correctly if Intel Turbo Boost technology is on and “CPU C State” parameter is off, but I hoped that Intel mainboard did know how to do it. In fact, the maximum multiplier for our Intel Core i7-860 processor is 22x, but we can only disable “CPU C State” in the next section called “Power”.

I can understand Intel’s formal logics here. “Enhanced Intel SpeedStep Tech” and “CPU C State” parameters do deal with processor power supply and power-saving technologies that is why it makes sense to include them into the “Power” section. But what do we get in the end? Most processor-related parameters are in the “Performance” section, some are in the “Power” section, but it is in the “Main” section that we can select the number of active cores, enable or disable Intel Hyper-Threading technology. Don’t you think that it causes a little too much running around?

Let’s move on. Now we get to the “Boot” section. It is one of those rare occasions that we don’t have any complaints or issues. On the contrary, the level of detail in this section for Intel mainboard settings configuration is even superior to those we saw by other manufacturers. If you believe that there are too many options in this section, then you can use “Boot Menu Type” parameter to cut them down.

We have high expectation s for the next sub-section called “Boot Display Options”, but we still can’t find an option that would allow us to take down the boot-up image.

You can replace the image, but you can’t remove it completely. The list of supported hot keys is visible and clear, you can notice the changing POST codes in the lower right corner, but I personally would also like to see the information on the CPU, memory and connected drives, which we normally get from other mainboards.

The last section called “Exit” has not only the traditional options like “Save and Quit” or “Quit without Saving”, but also a few additional parameters that allow you to save and load a complete BIOS settings profile. There is only one profile you can save and unfortunately, you can’t change its name or add a description for it.

One more time Intel DP55KG mainboard doesn’t give us any reasons to be raving. Of course, they do a lot of work, but every positive change (slight adjustment of the BIOS structure and elimination of duplicating names) will still be compensated by a negative one (terrible color scheme). The board has almost everything necessary for successful system configuring from a formal standpoint, but software developers have to double their effort and work really hard to make sure that at least some time in the near future the BIOS of Intel mainboards becomes convenient and easy to work with.

Testbed Configuration

We performed all our experiments on the following test platform:

We used Microsoft Windows 7 Ultimate (Microsoft Windows, Version 6.1, Build 7600) operating system, Intel Chipset Software Installation Utility version, ATI Catalyst 9.9 graphics card driver.

Intel Desktop Control Center

Frankly speaking, I wasn’t going to mention Intel Desktop Control Center (IDCC) tool, but we have already talked about it a while back, so I can’t just pretend that it never existed. In this case I would prefer to stick to just a few words, but again looks like it is not an option. Therefore, let me explain why we had to install this program at all in the first place. The thing is that “HWMonitor" utility, which I usually use couldn’t show the rotation speed of the processor cooling fan. By the way, as soon as I installed IDCC it stopped showing the voltages, too. In the meantime Intel DP55KG mainboard has very low startup fan speed of only 500 RPM. It is good, it is very quiet, but I couldn’t determine by ear if the fan rotation speed was increasing under load, namely, if the fan rotation speed control feature was working at all. To answer this question I needed to install IDCC.

The program looks exactly the same, nothing changed: a humongous window still take up half of my desktop space and this reason alone is good enough to make working with this tool extremely inconvenient. But let’s put convenience of use aside, as well as the fact that IDCC can’t show the current CPU clock frequency, and go straight to the monitoring section.

There is very little info here, just like in the corresponding section of the Intel DP55KG mainboard BIOS, but most importantly, all numbers are static. Nothing is changing: the voltages as well as fan rotation speed remain the same all the time. It doesn’t really monitor anything, but merely displays the numbers registered during program launch. By the way, you can notice that the voltage readings are different: there is 1.13 V in the mainboard window, and 1.12 V in the monitoring window, while the normal voltage settings should be 1.10 V. we saw the same exact difference at all times and in all operational modes. I wonder which of the two reported readings is in fact closer to reality?

It turned out that Everest utility suits best to monitor Intel DP55KG mainboard parameters. It controls not only the fans rotation speeds, but also all voltages, even those that are not mentioned in the IDCC, such as memory voltage. By the way, Intel DP55KG sets almost all voltages higher than what is set in the BIOS. However, we still couldn’t walk away from IDCC, because its settings have the priority over the BIOS settings. Namely, we suspected that it was the working fan rotation speed adjustment function that didn’t let the board show it real best during overclocking. Although we did disable this function in the BIOS, it turned back on immediately after we loaded Windows OS. We did increase the fan speed manually to maximum using IDCC, but even though later on we turned adjustment back on in the BIOS, the fan rotation speed again increased to its maximum after Windows loaded completely. We couldn’t lower the fan rotation speed anymore and when we tried to get back to the default settings, the program would hang.

We uninstalled IDCC and then installed it back on our system after completing all tests in order to take some screenshots for the review. And a miracle happened! After another reboot, monitoring suddenly started working! But who will actually need it if it only starts working after multiple system reboots and repeated program installations?

What else can IDCC do? It can overclock your system automatically. It requires long-term multi-step configuration procedure that takes place at night by default. Give it a try if you trust IDCC. As for me, I am confident that I can overclock my CPU better by myself.

Also, IDCC program can change almost any system parameters, starting from frequencies and voltages and ending with memory timings. However, there is one small but very serious issue here. Almost nothing happens right away. You can’t slightly adjust some selected settings right from Windows: any changes made to important parameters require a system reboot.

So, it appears that IDCC is a kind of a software superstructure over the BIOS. It is inconvenient, unreliable, unstable, and if you really have to reboot, then it would be easier to change the necessary parameter directly in the BIOS. The only advantage this program has over BIOS is the fact that it allows saving three user settings profiles, while in the BIOS you can only save one. However, this fact doesn’t highlight the advantages of the IDCC program but rather points out the drawbacks of the Intel mainboard BIOS. Other manufacturers’ solutions don’t have any restrictions like that. You may be able to find a way of using the functionality of Intel Desktop Control Center to your advantage, but I would prefer to put it aside for good.

Operational and Overclocking Specifics

We installed Intel Desktop Control center program to check if Intel DP55KG mainboard would increase the rotation speed of the processor fan under load. No it doesn’t if you are using a high-end processor cooler. It is good, because at 500 RPM you can’t really hear the fan working, but it is also bad because the load is pretty high and the heatsinks over processor voltage regulator components heat up quite substantially. They don’t get scorching hot, but they heat up way more than on other mainboards, they need more airflow coming their way, although the CPU temperature in this case remains within acceptable limits.

However, processor fan rotation speed control feature does work on Intel DP55KG mainboard. We could really tell without any programs or utilities when we started our overclocking experiments. For initial stability check we use LinX utility – this is a shell for Intel Linpack test that loads the CPU very heavily. This load is not constant, but cyclic. In the beginning of each calculations cycle the fan rotation speed increases rapidly to its maximum and then immediately dropped as soon as the cycle was over. This repeated howling of the fan makes it unbearable to work in close proximity of the Intel DP55KG mainboard. Moreover, the CPU temperature turned out significantly higher (by about 5°C) than on other mainboards in the same testing conditions or at constant maximum fan rotation speed.

5°C doesn’t seem like a big number, but 82°C is just a little over 80-degree threshold, while 87°C is already almost 90°C. At this point DFI LANPARTY DK P55-T3eH9 mainboard comes to mind, because we were also concerned about the efficiency of its fan rotation speed control function at first. While the maximum fan rotation speed was 2200 RPM, the board didn’t increase it beyond 1850 RPM. But it turned out that despite this fact, the difference in CPU temperature between the 1850 RPM and maximum rotation speed was only 1-2°C. So why would we need to speed up the fan even more if the current speed was already sufficient for proper cooling? We wouldn’t and that is why we really liked the principles of fan rotation speed control implemented in DFI mainboard, and didn’t like the ones used in Intel one. To be fair I have to say that even despite this acoustically unpleasant and not very efficient implementation of the fan rotation speed control feature, Intel DP55KG mainboard did provide sufficient cooling even for an overclocked processor. And with less stressful test applications the noise won’t be so significant. However, I still don’t think that the rotation speed control algorithms on Intel DP55KG can be considered a success. Besides, we can’t adjust them in the BIOS, like we could on other mainboards, or using the IDCC tool. The latter only allows locking the rotation speed at a certain selected value.

CPU overclocking on Intel DP55KG mainboard also caused us some problems. It could only work at 200 MHz base clock, while many other mainboards we tested before allowed us to go as high as 210 MHz. So, it shouldn’t be surprising that the maximum CPU overclocking on Intel DP55KG stopped at 3.9 GHz.

Like all other mainboards, Intel DP55KG keeps all processor power-saving technologies up and running during dynamic Vcore increase. Not only the processor clock frequency multiplier but also the its core voltage will lower in idle mode.

Performance Comparison

Time has come to check out the performance numbers and compare the results in two different system modes: in nominal mode and during CPU and memory overclocking. First we are going to talk about the results in nominal mode, when the boards set the most optimal parameters on their own, almost without any help from the user. Due to Intel Turbo Boost technology the clock frequency multiplier of our Intel Core i7-860 processor could increase to 26x. Our today’s hero will be competing against previously tested mainboards. The mainboards are listed on the diagrams according to their performance (from high to low). The results of Intel DP55KG mainboard are marked with a darker color for your convenience.

In order to adequately estimate the performance of Intel DP55KG mainboard, we should recall that in nominal mode Gigabyte solutions set higher base clock frequency, and ASRock P55 Deluxe was caught exploiting an even great increase, therefore, they are guaranteed faster than the other solutions. Biostar TPower I55 mainboard has peculiarities of its own: even with Turbo Boost technology it doesn’t always increase the processor clock frequency multiplier that is why it often falls behind the others in the nominal mode. So, the only other solutions that will compete against Intel DP55KG on equal terms are Asus P7P55D Deluxe and DFI LANPARTY DK P55-T3eH9.

Keeping in mind everything I have just said, we can see that Intel DP55KG mainboard doesn’t show an even pattern. It is sometimes ahead of the competitors in its group (for example, in Cinebench 10 and Custom PC Bench 2007 Video Encoding tests). Sometimes it appeared the slowest of all, even falling behind Biostar solution. In most cases the performance difference is minor, but in some it is fairly noticeable and cannot be written off as a measuring error, like in Custom PC Bench 2007 Image Editing test, for instance.

The second comparison was performed during maximum processor overclocking. This time we disabled extended processor power-saving modes in the mainboard BIOS using “C-STATE” parameter, which limited the maximum processor clock frequency multiplier setting with 22x. In this case the CPU could work at higher base clock than with 26x multiplier, which meant that we ended up with higher resulting performance although it happened at the expense of higher power consumption in idle mode.

We can see a different segregation during our performance tests during CPU and memory overclocking. Only Asus and Gigabyte boards could overclock our test CPU to 3.95 GHz. All others including Intel DP55KG stopped at 3.9 GHz. Intel DP55KG solution is very close to the leaders in 3DMark vantage and FarCry 2 tests, but the performance in these applications is mostly determined by the graphics card that is why the difference between mainboards is minimal. In most cases Intel DP55KG performance would be closer to the bottom of the list, but unlike the results in the nominal mode, its performance is not too different from that of the other competitors: there is no serious lag in any of the benchmarks.

Overall, Intel DP55KG performance in nominal mode and during CPU and memory overclocking is not surprising. In most cases it is as fast as the other boards, with very few surges and just as few drops. In fact, we didn’t expect our power consumption tests to reveal anything unusual either, but this was where the board really caught us unawares and puzzled with completely unreal results.

Power Consumption

We measured power consumption using Extech Power Analyzer 380803 device. This device was connected before the system PSU, i.e. it measured the power consumption of the entire system without the monitor, including the power losses that occur in the PSU itself. When we took the power readings in idle mode, the system was completely idle: there were even no requests sent to the hard drive at that time. We used LinX program to load the Intel Core i7-860 CPU. For more illustrative picture we created a graph showing the power consumption growth depending on the increase in CPU utilization as the number of active computational threads in LinX changed in nominal mode as well as during overclocking. Besides DFI LANPARTY DK P55-T3eH9 we also included the results for all previously tested LGA1156 mainboards.

Frankly speaking, if I hadn’t been the one running all these tests, I would have never believed the results I saw. It can’t be that the board showing the same power consumption in idle mode as all other solutions would demand more and more energy as the workload grew higher.  Under maximum load the power consumption difference reached 50 W compared with the least efficient mainboard, which until now has been a DFI solution, and 60 W compared with most of the other tested mainboards! It is totally unbelievable! And I didn’t believe it and started retesting and rechecking everything over and over again, making sure that I didn’t forget to bring down to nominal all the voltages in the mainboard BIOS. Nope, I didn’t, all optimal settings were in place, but the board kept consuming enormous amounts of power. So what are we going to get during CPU overclocking? Power consumption close to an inflammability limit? No, the results demonstrated by Intel DP55KG mainboard were hardly any different from everyone else’s.

Equipment doesn’t lie, and if it does then not so dramatically.  If the results are repeatable, then no matter how unrealistic they seem, there should be a logical explanation. Now we just have to find one. Why is the power consumption of Intel DP55KG mainboard almost the same as that of all other testing participants during overclocking and so unbelievably high in nominal mode?

One of the possible explanations is the way the board sets higher voltages on its own. In nominal mode nothing could prevent it from doing that, as we barely change the automatic settings. During overclocking, however, we kept in mind this peculiarity of the board and set the voltages lower than necessary, so that the resulting values could turn out exactly what we needed them to be. Yes, it could explain a 10 W difference, maybe a 20 W one, but not a 50-60 W difference!

The second hypothesis is the use of non-optimal algorithms for processor fan rotation speed adjustment. The board maintains very low processor fan rotation speed of less than 500 RPM. It is enough for a high-performance cooler to keep the CPU temperature in nominal mode within acceptable range even under heavy load, but the processor voltage regulator components heat up more than usual in this case because they lack airflow. The higher the temperature, the higher the power consumption. Pretty logical, but a 50-60 W difference is still way too big. Besides, this assumption doesn’t explain normal power consumption during overclocking. In this case the rotation speed control feature uses the same non-optimal algorithms, even the CPU temperature is higher, but the power consumption of Intel DP55KG mainboard is not any different from the rest of the testing participants.

So, looks like the third explanation makes most sense of all: processor voltage regulator circuitry is not functioning properly or is not designed correctly. Only under heavy processor load created during overclocking it proved efficient enough, but wastes a ton of energy when the CPU runs in its nominal mode.

Well, let’s check things out now. I can’t uncover the defects inside the processor voltage regulator circuitry on my own, but I can manually adjust the voltages in nominal mode and see how it affects the power consumption readings. I can set the fan at its maximum rotation speed and repeat the tests to see how the power consumption changes. Finally, I can do both at the same time. So, you can imagine how surprised I was when even before I made any changes to the testing conditions for Intel DP55KG mainboard, its power consumption in the nominal mode got close to normal.

So, let’s replay everything one more time. At first we overclocked our processor and ran the performance and power consumption tests. Then we loaded the optimal system settings and ran the tests one more time and this is when the power consumption of Intel DP55KG mainboard turned out considerably higher than the rest. After that I reflashed the old BIOS version back onto the board to take the screenshots for the review and then returned to the latest BIOS at the time of tests. Could reflashing the BIOS one more time have brought the board back to its normal operational mode? Let’s see. We overclock the processor one more time. By the way, I have already said that the early BIOS versions for Intel DP55KG mainboard do not have the utility for updating the BIOS and do not allow saving user settings profiles. However, despite the fact that we reflashed the BIOS twice already, the overclocking settings profile remained intact.

So, we overclock the processor one more time, then load the optimal system configuration settings and check the power consumption. Yes, the results are again incredibly high. Let’s try and set the CPU Vcore manually as close to the nominal as we can, and again the board’s power consumption comes back down to normal levels. So, here is what’s going on: when we load optimal system settings, the board doesn’t change the voltages back to their nominal values. Everything in the BIOS looks the way it is supposed to, but in reality only the frequencies get lowered, all other parameters go back to their nominal settings, but not the voltages: these remain where they were during CPU overclocking. You can’t notice it in idle mode, because the voltages are lowered by operational processor power-saving technologies. But under heavy load core voltage increases resulting in abnormally high power consumption. All our super-high power consumption readings taken off Intel DP55KG mainboard were correct and completely real and can be explained by a BIOS error.

Further tests showed that you don’t need to reflash the BIOS to bring Intel DP55KG mainboard back to normal. Just use the onboard jumper or a back panel button that will return all settings to their nominal values. Now it is the right time to run our power consumption tests, when Intel DP55KG really does work in its nominal mode.

As you see, things are far from the catastrophe we have anticipated after the first round of tests. The power consumption of Intel DP55KG mainboard in nominal mode turned out comparable with that of other mainboards. However, the users who only tried once to overclock their processor on Intel DP55KG and then went back to the nominal system settings, did not really know that they mainboard started to consume way more power. And the result of 50-60 W is definitely not the limit. The higher you set the voltages during your overclocking experiments, the more power will Intel DP55KG mainboard consume. Make sure you use the jumper or button to return the board back to normal.


Individual benefits that Intel DP55KG mainboard offered us during our test session got totally overshadowed by numerous small inconveniences and drawbacks. The most positive impression was definitely left by the fun skull that blinks eyes in accordance with the HDD activity. We could also give Intel DP55KG due credit for adequate cooling system without any extra heatsinks and heatpipes. We were also pleased with partially restructured BIOS, detailed settings in the “Boot” section, very well explained memory modules installation principles and a special guide for system configuring. I would consider the integrated Bluetooth controller more of a drawback than advantage, because it actually cost us two USB ports. One of them is occupied by the controller, while the internal port is really hard to work with, but as for the Bluetooth, anyone can go and buy a separate Bluetooth controller as a dongle, for instance.

I believe I didn’t leave out any of the advantages, but as for the drawbacks, I wouldn’t insist on continuing the list at this point. Among them are: not the best mainboard layout, inconvenient BIOS structure with annoying color scheme, errors in guides and manuals, insufficient processor overclocking… Most of the drawbacks are really small ones, but they are quite numerous. Besides, all these problems are overshadowed by a very serious BIOS error that can make the board’s power consumption horrendously high. I am pretty sure that they will soon fix it, but Intel developers still have to work really hard before their mainboards become user-friendly and easy to work with, start setting a real example to other manufacturers. “Kingsberg” – the codename of this solution – translates as “king of the hill”. Unfortunately, this mainboard is not yet that good, but it certainly has potential.