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Two GeForce 7950GT by Chaintech and MSIAuthor: Dmitry SofronovDate: 21/10/2006
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Today, we are examining two video cards based on GeForce 7950GT which NVIDIA announced in September along with the GeForce 7900GS chip. We are already familiar with one of the video cards based on 7900GS. Therefore, a joint announcement of these two solutions is quite logical. In fact, both 7900GS and 7950GT have the same roots. Both these chips are derivatives of 7900GT which by now has been laid off production. While 7900GS is produced through a cut-down in the number of pipelines to 20/7, the 7950GT has preserved its pipelines at 24/8 but acquired much higher clock speeds. That is understandable. The finer process technology favors to good overclocking, so why not to earn some more with that? The G71 chip has already been polished to the full, so operation at increased clock speeds is not risky for stability.
The first video card which we are examining today is one produced by Chaintech Walton Corp. The financial contributions by Walton which acquired Chaintech was not in vain, and the merged company is increasingly active at production of novelties and their marketing. Let's see what engineers at Chaintech have got for us this time.
The setting of the box is traditional for Chaintech produce. A lot of varied labels on the front side give a visual idea of the supported technologies. More interesting info can be found on the box side where it says that the GPU frequency is 550 MHz. That is the frequency recommended by NVIDIA for 7950GT. Running ahead, we say that the real GPU frequency of the specimen that has been to our test lab was 605 MHz, that is, the video card runs by default at somehow overclocked speed. There is no contradiction about that. The thing is that we got a video card of the "speedy" series called APOGEE, but by that time the boxes for these video cards had not yet been ready. You can take a look at how they should look over here.
The reverse side of the box for "regular" 7950GT video cards looks ordinarily. Along with the cliches of supported technologies, there is a list of accessories which are part of the video card's package bundle. Since we are reviewing an "advanced" version of the video card, the kit of its accessories will be somehow different. The package bundle includes:
Chaintech's video cards of the APOGEE series make a substantial difference from reference video cards, and primarily due to the installation of a Zalman cooler. Use of these powerful and noiseless coolers saves the ears of the user and allows boosting performance of the video card due to the rise of the VPU frequency.
As was already stated, the 7950GT chip is a derivative of 7900GT, so the PCB design has remained the same. That is well seen on the photo with the cooler removed. We've seen a similar PCB layout on both 7900GT and 7900GS video cards. We should not reproach the developers with laziness simply because this approach is easy and cost-effective.
Nothing to say about the reverse side of the PCB. It is the same "reference" which we've seen many times.
The GPU of 7950GT nor makes much difference from its brethren in class. The size of the chip, layout of the bridges - all has remained the way it used to be. Only the "GT2" characters have been added to the marking of the chip. To all appearances, for NVIDIA the new chip is simply a speedier version of the regular 7900GT. The VPU of Chaintech 7950GT APOGEE runs at 605 MHz. As compared to the recommended 550 MHz, the frequency has gone up by 10%.
The overall onboard memory capacity on Chaintech 7950GT APOGEE amounts to 512 MB. That is another difference from the "regular" 7900GT video cards which were normally equipped with merely 256 MB of video memory. The increase in capacity has been achieved due to use of 512-Mbit chips. The chips are made by Infineon, the access time is 1.4 ns, which is equivalent to the nominal 1400 MHz DDR frequency. The nominal operating memory frequency of Chaintech 7950GT APOGEE is 1540 MHz DDR. As we can see, the frequency is again increased by 10%.
The second video card which we are examining today is made by MSI. The sound conservatism and innovative approach have been fully reflected in MSI 7950GT Zero Edition. But - all in good time.
The setting of the box is quite traditional. Among the most essential points to note is the support for HDCP, as well as Heroes of Might and Magic V as a bonus item, and a proprietary noiseless cooling system due to which the video card has acquired the Zero Edition suffix.
The reverse side of boxes for MSI video cards almost never changes. These days, they start promoting yellow connectors which support the 2560õ1600 resolution, but this resolution is supported by all other offerings. If we compare this video card versus the Chaintech offering, the MSI video card supports 10% overclocking using the same proprietary D.O.T. Express technology. However, in the case of MSI 7950GT Zero Edition we should not be hasty at overclocking. Let me explain why.
MSI 7950GT Zero Edition uses a passive cooling system based on heat pipes. On the front side of the PCB, we can see merely a part of the cooler which adjoins the GPU. Evidently, the PCB design is absolutely the same as in all the other video cards of the 7900GS/GT series video cards. Among the pleasant surprises is the VIVO chip made by Philips. Lately, it's not often that you can see support for the video capture feature on video cards equipped with NVIDIA chips.
The reverse side of the MSI 7950GT Zero Edition is half hidden by a huge radiator of copper plates attached on heat pipes coming out of the video processor. Such a layout of the radiator is justified, since the air flow from the CPU cooler simultaneously blows about the video card radiator. However, we can bring in a number of examples when the design of the CPU cooler assumes a different structure of air flows. In this case, the efficiency of rejecting heat off the GPU may be reduced.
Another important point to dwell is the dimensions of the radiator. The thickness of the radiator is 17 mm (the distance from the PCB plane to the external plane of the radiator),so there may be issues when installing the video card on a motherboard with a huge radiator on the chipset or full-length memory modules having protective radiators.
We are not bringing in a photo of the radiator because it is unlikely to make any difference from the one installed on the Chaintech video card, and we also wouldn't like to dismantle the housing. The GPU operating frequency on MSI 7950GT Zero Edition fully meets the 550 MHz recommended by NVIDIA.
As regards the video memory, it is precisely the same. The overall capacity is 512 MB, the chips are made by Infineon, and the access time is 1.4 ns. The memory operating frequency coincides with the nominal and equals 1400 MHz DDR.
And this is a video capture chip made by Philips.
Package bundle of MSI 7950GT Zero Edition:
At that, we'd better stop with the exterior of these video cards and move on to the tests for overclocking and performance.
We first tested the thermal regime of Chaintech 7950GT APOGEE, and this is what we got in the end.
As you can see, the Zalman cooler does a fantastic job of cooling the video processor, and its temperature never exceeds 65°C. Of course, we tried to overclock the card even further, and this is what we got in the end. Despite that the temperature of the chip did not exceed 66°, we failed to attain a stable operation at neither 690 MHz nor 675 MHz. That is, the video card did work, but because of the "freezes" the final result proved to be worse than that in the nominal mode. So we decided to stop at 650 MHz for the GPU. At this frequency, there were no freezes, and the results went up substantially. We also tried overclocking the video memory, but it failed to reach 1600 MHz - the system hung. So we decided to stop at the nominal frequency.
We performed a monitoring of the GPU temperature for MSI 7950GT Zero Edition as well.
Frankly, the results were really fantastic. At the nominal frequencies, the GPU temperature under load was almost as high as 100°. The video card was running stably, but such a high temperature causes some anxiety. We ran the tests on a open test-bench, but the CPU cooler was blowing air towards the connectors of the rear panel of the motherboard but not towards the video card. We did not use additional fans. Perhaps that was the cause of such heating. So when buying a MSI 7950GT Zero Edition we strongly recommend that you fit fans on the rear panel of the CPU unit. At that same, this recommendation applies to all cases of using video cards equipped with passive cooling.
Nevertheless, we did try overclocking the video card by MSI. The results are the following – 625/1550 MHz. Interestingly, when cooling the radiator of the video card with an additional fan we were able to overclock the GPU again to the same 650 MHz. To all appearances, it's not the temperature that is an obstacle to further overclocking. Perhaps with opening the volt mode the 7950GT video cards will get a "second wind", but that is a different story.
Interestingly, the 7950GT overclocked to 650/1550 MHz very much resembles the formerly top-end 7900GTX video card whose default frequencies are 650/1600 MHz. Since the frequencies of video cards are close and the pipeline formula is the same, we can expect their performance to be on the same level. We will now verify now whether it is true or not.
We'll be comparing both the novelties based on 7950GT versus the "good old" 7900GT/GTX.
For tests, we used NVIDIA ForceWare 92.91 drivers.
As you can see from the diagrams, at performance the new GeForce 7950GT chip finds itself almost in the middle between 7900GT and 7900GTX, and if there is good cooling it is even able catching up with the latter. As regards the video cards reviewed today, the Chaintech product is somehow more preferable for games since it offers a quiet cooler and is already factory-overclocked. The MSI video card appears to be a good candidate for a media center since it offers support for the HDCP and VIVO. Needless to say, we should not forget about the good cooling of the interior of such a media center. The recommended price for these 7950GT video cards is $300-$350.
Bus
PCI-Express
CPU
MB
Memory
OS
WinXP + SP2 + DirectX 9.0c
PSU
Thermaltake ToughPower 750 W
3DMark
Half-Life 2
DOOM 3
F.E.A.R.
Final Words
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