All performance tests were run on the following test platform:
- Mainboard: Asus Maximus IV Extreme rev. 1.02 (LGA1155, Intel P67 Express, BIOS version 1850);
- Intel Core i5-2500K CPU (3.3 GHz, Sandy Bridge, LGA1155);
- 2 x 2048 MB DDR3 SDRAM Patriot Extreme Performance Viper II Sector 5 Series PC3-16000, PVV34G2000LLKB (2000 MHz, 8-8-8-24 timings, 1.65 V voltage);
- MSI N570GTX-M2D12D5/OC graphics card (Nvidia GeForce GTX 570, GF110, 40 nm, 786/4200 MHz, 320-bit GDDR5 1280 MB);
- Kingston SSD Now V+ Series (SNVP325-S2, 128 GB);
- Cooling system: Scythe Mugen 2 Revision B (SCMG-2100) CPU cooler and an additional 80x80 mm fan for cooling of the area around the CPU socket during overclocking experiments;
- ARCTIC MX-2 thermal interface;
- CoolerMaster RealPower M850 PSU (RS-850-ESBA);
- Open testbed built using Antec Skeleton system case.
We used Microsoft Windows 7 Ultimate SP1 64 bit (Microsoft Windows, Version 6.1, Build 7601: Service Pack 1) operating system, Intel Chipset Software Installation Utility version 184.108.40.2060, Nvidia GeForce Driver 280.26 graphics card driver.
Operational and Overclocking Specifics
As opposed to the ASUS P8P67 Deluxe and P8Z68 Deluxe mainboards with which we had some problems installing our Scythe Mugen 2 cooler, the Maximus IV Extreme didn’t present any such difficulties. We only had to look up in the user manual what SATA 6 Gbit/s connectors belonged to the chipset rather than to the onboard controller because all of the four SATA 6 Gbit/s ports are the same color of red.
Having assembled our test configuration, we were surprised to find that the mainboard wasn't working right in its default mode. Our Intel Core i5-2500K processor with a default clock rate of 3.3 GHz is supposed to have a frequency multiplier of x34 at full load but can be clocked at 3.7 GHz at low loads (when only one of its four cores is in use). However, the Maximus IV Extreme would increase the clock rate of our CPU to 3.7 GHz irrespective of load, even when all of the CPU cores were in use.
It’s good to have some more speed, but we guess that nonstandard operation modes should be left for the user to select rather than enabled automatically. As a matter of fact, we still have bad memories of a mainboard that would set the CPU multiplier at x37 irrespective of load. That was a Zotac Z68-ITX WiFi and it not only broke down itself but also burned our CPU. Zotac has the excuse of having tried to bring that mainboard to market as soon as possible without polishing its BIOS off (or maybe we were just not lucky and had a defective sample) whereas the Maximus IV Extreme has been around for a long time already and its firmware has been updated a few times. So, we don't like the incorrect operation of the mainboard in its default mode.
Fortunately, as opposed to the Zotac, the Maximus IV Extreme can be made to work normally. It is clear that the problem is in Turbo technology increasing the CPU multiplier to x37. When selecting optimal values in the BIOS, the mainboard sets Turbo Ratio at All Cores Mode. Oddly enough, this increases the CPU clock rate at 3.7 GHz at any load even though the Maximum Turbo Ratio Setting is set at Auto.
Now what if we set Turbo Ratio at “By Number of Active Cores Mode” without changing anything else? Well, this only makes things worse. The CPU multiplier is now always x37, even if there is no CPU load at all. The CPU voltage is also increased always, indicating that the CPU’s power-saving technologies have turned off.
Let’s try to set the Turbo Ratio at Auto, just like it should be by default. The mainboard starts up but cannot boot the OS and goes for a reboot automatically. It’s only after a few unsuccessful restarts that the mainboard returns to the truly normal default mode. From this moment on, it will work correctly until you load the optimal settings into its BIOS again.
Thus, the Maximus IV Extreme can be made to work normally but it doesn’t do that by default. Now what about overclocking? Unfortunately, this model lacks the handy OC Tuner Utility available in the BIOS of some LGA1156 products from ASUS. When selected, this utility can increase the base clock rate step by step, restarting the mainboard after each increase. LGA1155 processors are overclocked by increasing the frequency multiplier rather than the base clock rate and ASUS may just have not found an algorithm to implement this. Instead, you can use the CPU Level Up feature which increases the CPU clock rate to 4.2 or 4.6 GHz. This way of overclocking, typical of MSI mainboards, is not optimal, though. The CPU multiplier and voltage are increased but the power-saving technologies get disabled, so the CPU just works at the set frequency without lowering it and the voltage when idle.
In our recent review of the Gigabyte G1.Sniper 2 mainboard we praised its automatic overclocking feature called O.C.Button. When the button is pressed again or the system is rebooted, the mainboard returns to its default settings, which means that you don't have to keep your computer overclocked all the time but can get a performance boost only when you really need it.
ASUS mainboards have long had a Go button which serves the same purpose. Moreover, with Gigabyte mainboards you have to use automatically selected parameters whereas ASUS ones allow you to specify what parameters are going to be used when you press Go. On the other hand, Gigabyte makes the O.C.Button easily accessible via a control panel you can insert into a 5.25-inch bay. ASUS's Go button is only easy to use on an open testbed. We don't think anyone uses it on a regular basis.
Well, you shouldn't be disappointed at the lack of adequate automatic overclocking features with the Maximus IV Extreme because the mainboard behaves very well when overclocked manually. It could easily overclock our CPU to its maximum 4.7 GHz and we didn't even have to increase the CPU voltage as much as on other mainboards. Besides, our memory modules were perfectly stable at 1866 MHz.
We always overclock mainboards in such a way that they could be used permanently in such mode. Therefore we do not disable any features, e.g. onboard controllers, and try to keep the CPU's power-saving features up and running. The Maximus IV Extreme was overclocked in this manner, too. When idle, it lowered the CPU's voltage and frequency multiplier to save power.
In our recent reviews we noted that it was only Gigabyte mainboards that could correctly report the frequency of an overclocked LGA1155 CPU when starting up. Other mainboards only report the correct memory frequency and the default CPU clock rate. The Maximus IV Extreme can also tell you the exact frequency of an overclocked CPU.
Our description of the mainboard’s features wouldn’t be complete if we didn't tell you about the software bundle included into its box. The DVD contains 3DMark Vantage Advanced Edition and Kaspersky antivirus with a 1-year license. The Maximus IV Extreme is also compatible with a number of exclusive tools which have been covered in our reviews of other ASUS products (they only differ with their special Republic of Gamers interfaces). There is only one significant difference due to the Maximus IV Extreme having a Bluetooth module. So, besides using the ROG Connect feature and a special cable for controlling the mainboard from another computer, you can do this wirelessly from a mobile device. The RC Bluetooth utility allows connecting to the mainboard from an Android, Symbian or Windows Mobile smartphone. If you've got an iPhone or iPad, you can use the ROG iDirect tool for the same purpose.