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- Date:
- Monday , July 09, 2007
- Author:
- Brent Justice
- Editor:
- Kyle Bennett
- Google +1
Sapphire Radeon HD 2900 XT CrossFire
Two retail Sapphire Radeon HD 2900 XT video cards, one Intel Bad Axe 2, and two CrossFire bridge connectors equals ATI’s most powerful graphics combination at this time for gaming. We find out if two Radeon HD 2900 XT video cards in CrossFire is worthy or a waste.
Elder Scrolls IV: Oblivion
(DirectX 9)
Oblivion uses the multi-platform Gamebryo game engine. Oblivion features DirectX 9 shaders and Havok physics. The engine supports lush vegetation, soft shadows, and high dynamic range lighting (HDR). Oblivion also features SpeedTree for rendering trees.
For testing we have chosen to do a manual run-through riding horseback from outside the Imperial City to Chorrol to Bruma. This run-through allows us to push the hardware as much as the game can. While this is an outdoor run-through we do make sure to test indoor situations in our gameplay analysis as well. We have found that turning on the torch indoors with HDR lighting takes a big hit on performance in some situations. We make sure to test this scenario. You really have to look at the game as two different scenarios, Outdoors and Indoors.
Standard Resolution
Out of all the games we tested Oblivion seems to be the “closest” between the single Sapphire Radeon HD 2900 XT and BFGTech GeForce 8800 GTS OC2 640MB. We were able to run at 1600x1200 with 2X AA and 16X AF enabled on the Sapphire HD 2900 XT. We did have to push the grass down to 25% of maximum, while all other in-game settings were at their highest values. With the BFGTech 8800 GTS OC2 we also found 2X AA and 16X AF playable at 1600x1200, but we were able to use 50% grass. There is a clear framerate difference, with the BFGTech 8800 GTS OC2 typically providing higher framerates in Oblivion, but the actually gameplay experience is very similar between the two video cards in this game.
When we installed two Sapphire Radeon HD 2900 XT video cards in CrossFire we did receive a performance boost in Oblivion. This performance boost was very noticeable and allowed us to set the grass to the highest level, besting the single BFGTech 8800 GTS OC2. We also found that we could increase antialiasing settings, and we had a choice. We found that you could set 4X AA, no Adaptive AA, and found this to be playable. Or, you could enable Quality Adaptive AA at 2X and play with that. Overall we found 2X Quality Adaptive AA to provide the best gameplay experience since Adaptive AA antialiases all vegetation in the game, such as the trees and grass. We did try pushing the CrossFire configuration to 8X AA at 1600x1200 but found that gameplay became very choppy.
In this screenshot you can see the benefit that two Sapphire HD 2900 XT’s in CrossFire bring to the game. We are able to have grass farther in the distance, and receive antialiasing on trees and grass.
Widescreen 2560x1600
At 2560x1600 comparing Sapphire Radeon HD 2900 XT in CrossFire to BFGTech GeForce 8800 GTS OC2 640MB in SLI we find them to be neck at neck. We had to disable AA on both the CrossFire and SLI setup in order to achieve playable performance. We did notice that when pushing the CrossFire configuration to 2X AA versus the SLI configuration, the CrossFire configuration was a lot more choppy than the SLI setup at 2X AA. Regardless, neither were playable with 2X AA. We were able however to have grass enabled at maximum, so we are experiencing the game at the highest in-game settings possible. Framerate wise the SLI configuration is faster, but since we found the same gameplay settings playable, there was no visual difference.
Interestingly enough the single GeForce 8800 Ultra is playable at a higher setting than the CrossFire or SLI configuration tested. Keep in mind the 8800 Ultra has 128 stream processors, compared to 96 on the GTS, and much higher clock speeds as well as more RAM, 768MB. We were able to run this single video card at 2560x1600 with 2X TR MSAA, but we did have to set grass down to 50%. Framerates were lower than the multi-GPU configurations, but the game was still playable.