Date:
Wednesday, March 23, 2005
Author:
Brent Justice
Editor:
Kyle Bennett
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NVIDIA SLI Support - Getting Better

A new driver from NVIDIA has improved SLI support and brought new features to the table. Inside we not only test this latest driver, focusing on SLI support and performance, but we also comment on what we would like to see in future iterations of NVIDIA’s SLI.

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DOOM 3

(OpenGL)

As our regular readers will know, we rely on FRAPS to record the framerate every second to create our gameplay performance over time graphs. We haven’t had any problems with FRAPS and SLI with either the previous ForceWare 66.93 or beta ForceWare 67.66 drivers in DOOM 3. However, once we installed the new ForceWare 71.84 drivers, we encountered a major problem with FRAPS. With the 71.84 drivers, we found that we were not receiving the performance benefit of SLI with FRAPS running. It was as if it was disabling the performance benefit of two video cards and running the game as if it were running on a single video card. We found performance to match that exactly of a single video card, even though SLI was enabled.

We found that this happens with any FRAPS version above 2.2.5, including the newest 2.5.3 version. However, we did have success with FRAPS version 2.2.5. Using version 2.2.5 of FRAPS we once again received the performance benefit of SLI. So if you use FRAPS yourself as a frame counter or for other reasons and you have an SLI setup in DOOM 3 with the ForceWare 71.84 drivers you will want to close down FRAPS or use version 2.2.5, or an earlier versions, of FRAPS. We have informed FRAPS.com of the problem.

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We are using the full retail version of DOOM 3 and leaving each video cards driver control panel to “Application Preference” for AA and AF. We set the DOOM 3 in-game quality setting and resolution that played the best on each card. We utilized the in-game DOOM 3 AA setting to change AA level.

For our manual run-through, we chose the “Enpro” level and used FRAPS version 2.2.5 to capture the framerate every second and started our run-through from the beginning to half way through the mission. We played the game in a normal fashion, which means each run-through on each card will be a little different, but it still represents the same course through the level.

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We evaluated DOOM 3 in our SLI Upgrade Guide with the previous official WHQL ForceWare 66.93 drivers here. Therefore, you can look back there and then look at the above graph to make some comparisons. What you will find is that there are really no changes in what the highest playable quality settings were with the GeForce 6800 GT. A single GeForce 6800 GT was playable at 1600x1200 with no AA and 8XAF and when you put two together in SLI, we were able to play at 1600x1200 with 4XAA and 8XAF. This puts the performance of two GeForce 6800 GTs in DOOM 3 above that of a single GeForce 6800 Ultra.

We saw no major performance differences between ForceWare 71.84 and ForceWare 66.93 in this game. The only issue was with versions 2.2.6 and later of FRAPS killing SLI performance with ForceWare 71.84 in this game.