NVIDIA's SLI: Part 3 - 6800 & 6600 GT

NFS: Underground 2

Publisher: Electronic Arts

The Need For Speed: Underground 2 is a game that we've spent a long time playing through recently, we've used it here to represent a typical driving simulator - it's based on the DirectX 9.0 API, and makes use of lots of DirectX 9.0 features, including motion blur and light trails. Anti-Aliasing was controlled from inside the game, while Anisotropic Filtering was controlled via the driver control panel, as the game does not feature in-game controls for Anisotropic Filtering.

We used a 3-lap race on the "Parkade Track 1" Street-X circuit with three opponents for our manual run through. The circuit is a fairly high-speed one, but contains lots of corners - it makes good use of motion blur and light trails.

This title uses an alternate frame rendering method, but it did not allow us to increase resolution at all with these video cards. However, with a single BFGTech GeForce 6600 GT OC, we found that 1024x768 0xAA 16xAF with Maximum quality settings delivered the highest playable image quality. Adding a second 6600 GT OC in to the fold for SLI allowed us to apply 2xAA to the scene, resulting in smooth game play at 1024x768 2xAA 16xAF with Maximum quality details.

With MSI's GeForce 6800 Std, we found that 1024x768 2xAA 16xAF with Maximum quality details delivered a smooth and pleasurable gaming experience. Adding in a second GeForce 6800 Std allowed us to attain smooth frame rates at 1024x768 4xAA 16xAF with the same maximum quality detail settings that we used on a single MSI GeForce 6800 Std. Again, adding a second video card for SLI allowed us to apply another 2xAA to our best-playable settings for a single video card solution.

Using a single XFX GeForce 6800 GT, we experienced smooth game play at 1024x768 4xAA 16xAF and maximum in-game details. We found that you can also play this game with a smooth frame rate at 1280x1024 0xAA 16xAF, and it really depends whether you prefer Anti-Aliasing over a higher resolution. In this case, we chose the lower resolution with Anti-Aliasing, as it removed a lot of the jaggies from the edges of the car.

We found that this title did not benefit from SLI as much as some, but that is because we feel that this title is CPU limited, and having a fast CPU really helps you to scale both resolution and Anti-Aliasing when you add in a second video card. However, we did see a performance increase, and you can experience even more performance improvements from overclocking your CPU a little. Most of today's Athlon 64's overclock pretty well, so you should at least be able to see an extra 200MHz core speed here and there.