maverik-sg1
New member
Half-Life 2 is a Direct3D game. By default, the CrossFire platform will enable SuperTile rendering mode in Direct3D titles unless a profile in Catalyst A.I. specifies otherwise. We suspect that ATI is using AFR as the rendering method in this game. We know that NVIDIA uses AFR in Half-Life 2 to extract the most performance in a dual card solution. By implementing CrossFire, we did experience a performance gain over a single Radeon X850 XT.
With a single Radeon X850 XT, we found that 1600x1200 with 2X anti-aliasing and 16X anisotropic filtering was the highest playable setting in the game. At this quality level, we had smooth performance even in the demanding Canals_09 map where the helicopter is throwing up water as you move along with mines being dropped on you. We did try to enable 4XAA on the single Radeon X850 XT, but performance was too slow in too many places. We also found the single GeForce 6800 Ultra to be playable at 1600x1200 with 2XAA. The single Radeon X850 XT was clearly faster than the GeForce 6800 Ultra in this game.
When we installed the Radeon X850 XT master card and enabled CrossFire mode, we found there was a noticeable performance increase. With this performance increase, we found we could enable 6X anti-aliasing at 1600x1200. Performance was very fast in the game at this high anti-aliasing setting in CrossFire. Keep in mind, however, the CrossFire platform does not support any kind of supersampling or transparency anti-aliasing so this is all multisampling. We did try to enable the Super AA modes in this game but performance was too slow even at Super AA 8X mode, and we encountered problems initially with these modes. With two GeForce 6800 Ultras in SLI, we found we could enable the highest in-game quality setting available, which was 4XAA.
We did not experience any problems in Half-Life 2 with the CrossFire platform in the normal 2X, 4X, and 6X in-game AA settings. However, initially when we first tried Super AA 8XAA, 10XAA, 12XAA, and 14XAA at 1600x1200, we experienced an odd graphical problem. There seemed to be severe ghosting in Half-Life 2. It was as if there was a delay in the graphics causing intense smearing or ghosting of everything on the screen. The game was completely unplayable with this problem.
The screenshot above illustrates the ghosting problem we encountered. We lowered the resolution all the way down to 1024x768, but we still experienced the problem.
I had planned to come back to it to investigate further, but strangely, for no apparent reason, the next time we fired Half-Life 2 up the problem had fixed itself and Super AA worked fine. We were able to take the screenshots for the Super AA screenshot comparison section just fine. I guess this is one of those strange problems that fixes itself. We thought we would note this though in case anyone out there has this problem crop up on them. We can’t think what would have caused it, and, frankly, we can’t figure out what fixed it. Add this to the list of odd quirks with CrossFire.
Comparing the single GeForce 7800 GTX to these dual card solutions is interesting. While the ATI Radeon X850 XT CrossFire setup allows 6X anti-aliasing, it is only multisampling so all alpha objects are very aliased. With the single GeForce 7800 GTX, we can easily enable transparency supersampling at 4X anti-aliasing mode, which provides a much better gaming experience in Half-Life 2. The single GeForce 7800 GTX offers better image quality and higher performance in Half-Life 2 compared to these dual card solutions.
