Tuesday, September 7, 2010

GeForce 8800 GTX/GTS Overclocking


Shortly after publishing our GeForce 8800 GTX/GTS Performance Preview article, we received quite a few requests for more info on our GeForce 8800 GTS overclocking experience. Quite a few of you were curious to see more performance numbers in games like Oblivion, while others wanted to see GeForce 8800 GTX overclocking results.

But the number one question we received by far was how we were able to achieve such high scores with the GeForce 8800 GTS. No one expected the overclocked GeForce 8800 GTS to be able to match, and in some cases outperform the GeForce 8800 GTX. After all, the 8800 GTS has a narrower 320-bit memory interface versus the 384-bit memory interface present on the GeForce 8800 GTX, and 32 of its stream processing units as well as one ROP have been disabled from the factory by NVIDIA. Not to mention the lower clock speeds for the graphics core and stream processors.

All this should mean that even a highly overclocked GeForce 8800 GTS shouldn?t be able to catch up to, much less outperform a stock GeForce 8800 GTX right?

Based on our testing last week, it looked like this wasn?t always the case. But we?ve since gone back and re-run our overclocked benchmarks and couldn?t replicate the astounding numbers we were seeing previously, even though we were using a different GTS card that was overclocking to even higher clock speeds!

Quite frankly, we?re still surprised by this, as we repeat our performance runs three times and take the average score for all of our official results. Under our latest round of overclocked testing, even the highest of those three runs didn?t equal the average we recorded previously in some games! Again, we?re still at a loss to explain the disparity, but we wanted to pass this info along as we know that many of you are currently debating between the two GPUs and want as much info as possible on this topic.

Fortunately, the news isn?t all bad for the GeForce 8800 GTS, even under our latest round of testing there are cases where it comes close to matching the GTX in performance, but often this occurs in cases where the graphics card is CPU-bound, such as in the case with Pacific Fighters and LOMAC, or in Quake 4 at 1280x1024. Remember that at lower resolutions with a card as powerful as the GeForce 8800, you?re often CPU-bound, particularly with titles that aren?t shader-intensive. We also still believe that with further driver updates, NVIDIA?s driver team will likely be able to wring more performance out of GeForce 8800.

As we?ve mentioned before, in order to overclock the GeForce 8800 cards, you?ll have to download NVIDIA?s nTune utility. The Coolbits registry hack doesn?t work and only prompts you to download nTune. In particular, you?ll need nTune 5.05 or better to overclock the GeForce 8800.

This isn?t a big deal if you already own an nForce motherboard, as nTune provides built-in overclocking options and BIOS settings for your motherboard all from within Windows, but for those of you who have already upgraded to P965 or 975X Core 2 motherboards this may be a bit of a disappointment as nTune is a 30MB+ app. In fact, it seems that as a result, some GeForce 8800 owners have turned to ATI Tool instead to overclock their graphics card.

NVIDIA plans to enhance nTune to make it more appealing for GeForce 8800 overclocking in the near future though. One feature that?s been mentioned is the ability to independently set the clocks for the graphics core and stream processors. Right now in nTune when you overclock the graphics core, you also overclock the stream processors by a fixed percentage.

We?d also like to see NVIDIA integrate GPU temperature monitoring on the same page as GPU clock speeds, as it has been done with Coolbits in the past. Currently the two are located in two totally different parts of nTune.

View the original article here

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