by Ilya Gavrichenkov
01/11/2007 | 04:09 PM
DFI has earned its reputation of the maker of high-quality overclocker-friendly products with its mainboards for AMD processors. Each new product from this brand is now received with high expectations by the overclocking community. We are trying to do our best to keep up with DFI’s product range and review the worthiest samples.
<%BANNER[article]%>A couple of months ago we got a DFI Infinity 975X/G mainboard based on the Intel 975X Express chipset and compatible with Core 2 series CPUs. Expecting to find it worthy of an overclocker’s interest, we put it into our testbed right away but were bitterly disappointed. Created by DFI’s best engineers, the mainboard didn’t do well at overclocking. Frankly speaking, it provided mediocre overclocking opportunities, obviously insufficient for us to recommend it to true overclockers.
Luckily, DFI doesn’t stop to work on a product after its release as some other manufacturers do. When we returned to the mainboard later, we found it greatly changed. The developer had managed to considerably improve its overclockability by issuing a few BIOS updates. Right now, the DFI Infinity 975X/G is surely a worthy product to be tested in our labs, especially as it is one of the cheapest i975X-based mainboards that supports the full range of Core 2 Duo, Core 2 Quad and Core 2 Extreme processors as well as ATI CrossFire technology.
Let's get started.
The discussed mainboard belongs to the Infinity series and this explains a lot. Unlike the famous DFI LanParty UT, the Infinity series includes value mainboards for enthusiasts. Thus, the DFI Infinity 975X/G is an as-cheap-as-possible product which is, however, based on an expensive chipset from Intel. This approach has resulted in a most exciting product. In fact, the Infinity 975X/G lacks any competitors in its price category. It is currently the cheapest mainboard with support for CrossFire.
Not surprisingly, the list of the mainboard’s specs isn’t long. And it looks rather plain itself: you don’t often see the standard green textolite in PCBs of mainboards for Core 2 CPUs. Well, we don’t care much about the externals, so let’s better take a look at the characteristics the DFI Infinity 975X/G is endowed with:
DFI Infinity 975 X / G | |
CPUs | LGA775 processors: Celeron D, Pentium 4, Pentium D, |
Chipset | Intel 975X Express (i975X + ICH7R) |
FSB frequencies | 100-533MHz (with 1MHz increment) |
Overclocking friendly functions | Adjustable processor core voltage, Vdimm |
Memory | 4 DDR2 DIMM slots for dual-channel |
PCI Express x 16 slots | 2 (work simultaneously in 8x mode) |
PCI Express x4 slots | 1 |
PCI Express x1 slots | 1 |
PCI expansion slots | 2 |
USB 2.0 ports | 8 (4 – on the rear panel) |
IEEE1394 ports | 2 IEEE1394a ports |
ATA-100/133 | 1 ATA-133 channel (in the chipset) |
Serial ATA | 4 Serial ATA-300 channels (in the chipset, with RAID support) |
ATA RAID support | RAID 0, 1, 0+1, 5 in the chipset |
Integrated sound | 8-channel HD codec: Realtek ALC882 |
Integrated LAN | Gigabit Ethernet controller: Realtek RTL8111B |
Additional features | None |
BIOS | Phoenix – AwardBIOS 6.00PG |
Form-factor | ATX, 305mm x 244mm |
Despite the total economy, they have found room to place three additional controllers: IEEE1394, eSATA and Gigabit Ethernet. Well, that’s actually the bare minimum for a mainboard to be considered modern.
DFI saved more on the accessories. Besides the mainboard, the box only contains a user manual, a CD and two diskettes with drivers, an I/O shield, two Serial ATA and one Parallel ATA cable. You don’t even get brackets with additional ports for the back panel of your system case.
All this stuff is parceled into a rather small box that has a carry handle anyway:
Besides a strange picture with Chinese hieroglyphics, the main features of the mainboard are listed on the sides of the box. We’ll discuss them right now.
The DFI Infinity 975X/G offers the same functionality as any other i975X-based product. It supports every modern LGA775 CPU with both Core and NetBurst micro-architectures. It offers four DDR2 DIMM slots for up to 8GB of system memory. The slots are color-coded to help you correctly install memory modules to enable the dual-channel mode. According to the specification, the mainboard supports DDR2-400/533/667/800 SDRAM, its frequency is selected in the BIOS Setup. Other memory frequencies, besides the standard ones, are not supported.
In the way of expansion, the DFI Infinity 975X/G offers two PCI slots, one PCI Express x1, one PCI Express x4, and two PCI Express x16, but its PCI Express x16 slots work as PCI Express x8 when you install two graphics cards into your system. If you don’t have a second graphics card, the second PCI Express x16 slot is disabled. This allows using the Infinity 975X/G as a foundation for a high-performance gaming station featuring ATI CrossFire technology. There are certain limitations concerning the other PCI Express slots. If you enable the PCI Express x4 in its native mode, the PCI Express x1 slot becomes disabled. But if you need to use the PCI Express x1 slot, you can do that by switching the PCI Express x4 into PCI Express x1 mode. The operation mode of these slots is selected with a jumper.
The mainboard’s South Bridge (ICH7R) supports RAID 0, 1, 0+1 and 5 and Matrix RAID. So, the hard disk drives you attach to the four available Serial ATA mainboards can be united into RAID arrays. NCQ and a data-transfer rate of 3Gbps are supported. The chipset also supports the Parallel ATA-100 port. DFI didn’t stop at that, though, and added an onboard PCI Express controller JMicron JMB360 that is responsible for the mainboard’s eSATA port. This external port for hard disk drives can be found on the mainboard’s I/O panel.
The South Bridge supports the mainboard’s eight USB 2.0 ports, four of which are located on the I/O panel and four more are onboard pin-connectors. To implement IEEE1394 ports, they installed a VIA VT6307 controller: one of its ports is on the mainboard’s I/O panel and the other is a pin-connector on its PCB.
The mainboard’s audio section is based on an eight-channel HD codec Realtek ALC882. It is soldered right on the PCB rather than on a separate Karajan module which is a customary feature of DFI’s LanParty UT series. The mainboard’s I/O panel offers six analog inputs and outputs as well as optical and coaxial SPDIF outputs.
The mainboard provides a Gigabit Ethernet connection by means of an integrated PCI Express controller Realtek RTL8111B.
An important component of the reviewed mainboard is an ITE IT8718F chip. Besides supporting the legacy ports, it provides hardware monitoring options and allows to control the speed of the fans depending on the temperatures read from sensors. The DFI Infinity 975X/G makes full use of the capabilities of this chip, giving you access not only to the readings of the sensors, but also to controlling the fan speeds in the BIOS Setup.
The IT8718F chip is also accessible from Windows through a utility called Smart Guardian. It is included with the mainboard.
Besides monitoring, this tool allows to control the operation of the fans.
A first impression about a product means a lot. If the mainboard looks good to you at first sight, you are willing to put up with its flaws later. That’s exactly the case with the Infinity 975X/G. Its rather low price, the good reputation of the manufacturer, and a few nice trifles implemented in the mainboard make one’s first impression about it favorable.
Let’s start with those trifles. Saving hard on the accessories and additional controllers, DFI didn’t try to do the same with the CPU power converter.
It is a six-channel converter on the Infinity 975X/G, incorporating high-quality capacitors from Nichicon. The MOSFETs in the CPU power circuit don’t have any cooling means, but they don’t really need any. The six-channel design guarantees low load on each of the channels, and the temperature of the MOSFETs is rarely higher than 40-45°C as a consequence.
A curious solution is employed to cool the mainboard’s chipset. While the leading mainboard makers are installing elaborate coolers with copper and heat pipes on their chipsets, DFI takes it easy:
There is just an aluminum needle-shaped heatsink on the chipset’s North Bridge which proves to be sufficient for cooling that chip. The manufacturer only recommends to mount a fan on it if you use a CPU cooler that doesn’t blow at this heatsink.
The South Bridge is covered with a ceramic plate about 1.5 millimeters thick. Thanks to its porous texture, the plate adds some originality to the mainboard’s appearance and also ensures a proper heat transfer.
Another nice trifle is the two micro-switches that serve as Power On and Reset buttons. They are indeed very helpful when you’re running your system without a system case.
The expansion slots are placed properly. The installed graphics card doesn’t block the latches of the DIMM slots. Besides that, the first PCI Express x16 slot is shifted away from the rest of PCI and PCI Express slots so that graphics cards with massive dual-slot coolers wouldn’t block any other expansion slot.
The only thing we can complain about is the position of the power connectors. They are behind the CPU, near the PCI Express x1 slot. It means that the thick ATX power cables will go right above the CPU cooler, interfering with its airflow.
The mainboard’s back panel offers a standard selection of ports: two PS/2 for the mouse and keyboard; four USB 2.0; one parallel port; one eSATA; one LAN port (RJ-45) with diagnostic LEDs; one FireWire; six analog audio jacks; optical and coaxial SPDIF outputs. The mainboard also has two serial ports, which are implemented as onboard headers.
DFI’s mainboards enjoy their high popularity not only due to their thought-through design, but also to their settings-rich BIOS that gives an overclocker a lot of options. Let’s see what the Infinity 975X/G can offer in this area.
The mainboard’s BIOS is based on Phoenix’ standard AwardBIOS 6.00PG microcode, but contains rather interesting options deep inside. Most of them are available in the Genie BIOS Setting section which is a kind of Control Center for all your overclocking activities.
Take note that our screenshots show one of the latest BIOS versions for this mainboard, dated December 1, so they differ greatly from screenshots you can see in other reviews of the same mainboard. DFI has changed the interface of the BIOS Setup, making it much more comprehensible.
The picture shows that there are not so many parameters here, yet everything necessary for overclocking is present:
That’s a sufficient selection of settings. The upper limits of voltages on the CPU and memory are very high, but the upper limit for voltage on the chipset’s North Bridge is rather low and this is going to be the main obstacle to your overclocking attempts with some CPUs. Well, we can understand DFI’s engineers here: the Infinity 975X/G has a too simple cooling solution on the chipset’s main piece. And if you are into extreme overclocking, you can improve the chipset’s cooling and modify the mainboard itself to increase the necessary voltage.
As for the memory subsystem options, the DFI Infinity 975X/G offers much more of them than regular i975X-based products – DFI’s mainboards have always featured enhanced memory configuring opportunities. However, the reviewed mainboard isn’t quite up to our expectations in terms of memory overclocking. It offers too few devisors to set the memory frequency.
For example, ASUS’ mainboards based on the same i975X chipset offer 3:4, 5:3 and 2:1 divisors (FSB:DRAM) besides the standard divisors of 4:3, 1:1, 5:4 and 3:2. DFI Infinity 975X/G doesn’t offer them.
The hardware monitoring page looks normal. You can monitor your system’s thermal and electrical parameters and choose the dependence between the temperature and the speed of the fans.
The reviewed mainboard not belonging to the LanParty UT series, its BIOS Setup lacks a CMOS Reloaded section typical of other products from DFI.
Now that we’ve become acquainted with the mainboard, it’s time to see what it can do at practical overclocking. To perform our experiments, we built a system with a DFI Infinity 975X/G, a Core 2 Duo E6300 CPU (its default clock rate is 1.86GHz), 2GB of DDR2 SDRAM (Corsair TWIN2X2048-8500C5), a PowerColor X1900 XTX 512MB graphics card, and a Western Digital WD1500AHFD hard disk drive. The i975X chipset often fails to work properly at memory frequencies of near 1GHz, so we set the biggest DDR2 frequency divisor of 4:3 for the time of our tests. The CPU was cooled with a Zalman CNPS9500 LED.
First we wanted to see what FSB frequency we could reach without changing the North Bridge voltage. It was quite predictable: at a FSB clock rate of 412MHz the mainboard is perfectly stable even at 1.6V on the chipset.
Like with other i975X-based mainboards, you can increase the FSB frequency higher by lifting up the voltage on the chipset’s North Bride first. The higher the voltage, the better results you can expect to achieve. The DFI Infinity 975X/G confirmed our point: the maximum of FSB frequency moved up to 451MHz after our setting 1.75V on the North Bridge.
This is quite a normal result for an i975X-based mainboard. Better overclocking can be achieved on those mainboards that allow setting a higher voltage on the chipset. Well, if 450MHz is too low for you, you can try to overclock your Infinity 975X/G using a volt-mod. Some overclockers have reported on the Web that they have conquered FSB frequencies above 500MHz on the Infinity 975X/G.
In our experiments we managed to overclock our Core 2 Duo E6300 to 3.15GHz. We achieved this by slightly increasing the CPU voltage, 0.1V above the default value. This indicates that the mainboard didn’t allow to reveal the full overclocking potential of the CPU. So, we can’t call the Infinity 975X/G an ideal platform for overclocking junior CPU models from the Core 2 Duo E6000 series.
The mainboard should do better with CPUs that have a bigger multiplier, but this is not always the case in practice. Our experiments on overclocking an engineering sample of the not-yet-announced Core 2 Duo E4300, expected to work with a 9x multiplier and a 200MHz FSB, were a fiasco.
Strangely enough, the highest FSB frequency the Infinity 975X/G was able to work with that CPU at was only 295MHz. That’s obviously not the limit for the CPU, yet the mainboard refused to pass the POST at higher FSB frequencies. So, there is clearly some incomplete compatibility of the mainboard’s BIOS with Core 2 processors that work with a 200MHz FSB by default. But considering DFI’s meticulous approach to supporting its own products, we hope this problem will soon get a solution.
And finally we want to benchmark our Infinity 975X/G in comparison with its competitors from ASUS and Intel that are also based on the i975X chipset. We’ll use the following hardware for this test:
Identical settings were selected in the mainboards’ BIOS Setup.
The diagrams show that the three mainboards – all based on the Intel 975X Express chipset – deliver roughly similar performance. The DFI Infinity 975X/G doesn’t differ from other mainboards on the same chipset in this aspect.
Although the DFI Infinity 975X/G mainboard doesn’t belong to the LanParty UT series the overclocking community favors so much, it has done well anyway. Having a low price, few accessories and a bare minimum of functionality, this mainboard isn’t worse than many other i975X-based products in terms of overclockability and performance. So, if its functionality suits you fine, you shouldn’t hesitate to take it as a CrossFire-ready platform for your Intel Core 2 processor.
Well, we shouldn’t be overpraising DFI after all. The Infinity 975X/G might have higher overclockability if the developer didn’t limit the opportunity to raise the voltage on the chipset’s North Bridge. That’s why some i975X-based mainboards are still better than the Infinity 975X/G is at overclocking processors.
Highs:
Lows:
And finally we want to remind you that if you do choose the DFI Infinity 975X/G, do not forget to update its BIOS! The mainboard overclocks processors much worse with early BIOS versions.