The NVIDIA GeForce 7900 GS: A Closer Look
by Josh Venning on September 19, 2006 5:00 AM EST- Posted in
- GPUs
Overclocking
As we mentioned in the introduction, and as we've seen in our performance tests, something to note with the 7900 GS is that it seems to be fairly good at overclocking. This is a factor that could potentially make the 7900 GS a formidable competitor to other cards in its price-range. Most of our 7900 GS's in this roundup have factory overclocks, but many users are interested in doing their own overclocking, so with this in mind, we've done some overclocking on these cards ourselves.
To get our overclocks, we use a method of gradually bumping up the clock speeds using coolbits, and then stress-testing the cards (using game benchmarks) to ensure stable operation at the highest possible clock speeds. "Stable Operation" is basically when a game benchmark runs without any tearing or graphical artifacts due to heat, and also without any lowered performance.
Every graphics card overclocks differently, and it's important to take some precautions when doing your own overclocking to avoid damaging your card. The speeds we achieved here do not necessarily reflect the exact overclock another XFX or EVGA 7900 GS owner might be able to achieve.
The XFX 7900 GS was one of our cards that overclocked especially well, along with the EVGA 7900 GS KO. Two of our 7900 GS cards that came with fairly modest factory overclocks managed to achieve higher user overclocks than the others. Unfortunately, the card with the lowest factory clock, the Albatron 7900 GS, also got the lowest user overclock, which is something of a drawback for this particular card. Below are the performance results at these clock speeds.
The data here shows the kind of improved performance these cards are capable of with further overclocking beyond the factory clocks. As expected, performance was the highest with the overclocked XFX and EVGA 7900 GS cards, and the improvements in framerates are impressive. In Oblivion for example, between the reference clocked Albatron 7900 GS and our user overclocked EVGA 7900 GS (591/812) at 1024x768, there is a 38% increase in performance. This kind of performance increase can mean the difference between being able to play at a higher resolution or with the quality settings turned up a little higher.
Even though the Albatron 7900 GS wasn't able to get as high of an overclock as the others, as the data shows, it still performs higher than most of the stock factory overclocked cards. Still, because there seems to be such variation between theses cards' overclocking ability, choosing the XFX or EVGA 7900 GS over the Albatron might be the best option if you plan to do your own overclocking. As we only have one sample of each card, we can't say for sure whether or not customers will be able match our overclocks or even exceed them, and as the saying goes your mileage may vary.
As we mentioned in the introduction, and as we've seen in our performance tests, something to note with the 7900 GS is that it seems to be fairly good at overclocking. This is a factor that could potentially make the 7900 GS a formidable competitor to other cards in its price-range. Most of our 7900 GS's in this roundup have factory overclocks, but many users are interested in doing their own overclocking, so with this in mind, we've done some overclocking on these cards ourselves.
To get our overclocks, we use a method of gradually bumping up the clock speeds using coolbits, and then stress-testing the cards (using game benchmarks) to ensure stable operation at the highest possible clock speeds. "Stable Operation" is basically when a game benchmark runs without any tearing or graphical artifacts due to heat, and also without any lowered performance.
Every graphics card overclocks differently, and it's important to take some precautions when doing your own overclocking to avoid damaging your card. The speeds we achieved here do not necessarily reflect the exact overclock another XFX or EVGA 7900 GS owner might be able to achieve.
GeForce 7900 GS Overclocking | ||
Manufacturer and Card | Factory Clock | User Overclock |
Albatron GeForce 7900 GS | 450/660 | 524/800 |
XFX GeForce 7900 GS RoHS Extreme | 480/700 | 597/824 |
EVGA e-GeForce 7900 GS KO | 500/690 | 591/812 |
Leadtek Winfast PX7900 GS TDH Extreme | 520/700 | 556/790 |
BFG GeForce 7900 GS OC | 540/660 | 571/751 |
The XFX 7900 GS was one of our cards that overclocked especially well, along with the EVGA 7900 GS KO. Two of our 7900 GS cards that came with fairly modest factory overclocks managed to achieve higher user overclocks than the others. Unfortunately, the card with the lowest factory clock, the Albatron 7900 GS, also got the lowest user overclock, which is something of a drawback for this particular card. Below are the performance results at these clock speeds.
The data here shows the kind of improved performance these cards are capable of with further overclocking beyond the factory clocks. As expected, performance was the highest with the overclocked XFX and EVGA 7900 GS cards, and the improvements in framerates are impressive. In Oblivion for example, between the reference clocked Albatron 7900 GS and our user overclocked EVGA 7900 GS (591/812) at 1024x768, there is a 38% increase in performance. This kind of performance increase can mean the difference between being able to play at a higher resolution or with the quality settings turned up a little higher.
Even though the Albatron 7900 GS wasn't able to get as high of an overclock as the others, as the data shows, it still performs higher than most of the stock factory overclocked cards. Still, because there seems to be such variation between theses cards' overclocking ability, choosing the XFX or EVGA 7900 GS over the Albatron might be the best option if you plan to do your own overclocking. As we only have one sample of each card, we can't say for sure whether or not customers will be able match our overclocks or even exceed them, and as the saying goes your mileage may vary.
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Josh Venning - Tuesday, September 19, 2006 - link
Thanks for the comment. We didn't include FSAA tests in this article because it isn't a full analysis of 7900 GS performance, but a comparison between different 7900 GS products. For an in-depth look at the 7900 GS performance in more games and settings take a look at the 7900 GS launch coverage(http://www.anandtech.com/video/showdoc.aspx?i=2827...">http://www.anandtech.com/video/showdoc.aspx?i=2827..., and the 7950 GT article which has some 7900 GS SLI numbers (http://www.anandtech.com/video/showdoc.aspx?i=2833...">http://www.anandtech.com/video/showdoc.aspx?i=2833....As far as driver settings, we test with default driver settings with the exception of vsync which is disabled. We do the same with ATI hardware; we leave catalyst AI on its default setting. We find this is the best way to keep our tests consistent for an article like this.
giantpandaman2 - Tuesday, September 19, 2006 - link
I wonder if part of the difference in heat/power consumption had to do with how much power was supplied to the fans. Slow running fan=low power=high heat. Faster fan=higher power=low heat.Meh, I'm not sure a tiny fan could ever put a dent in a 20 watt difference though.