I recently got my hands on another XFX 8600GT and decided to try out SLI with my other XFX 8600GT. First, here are some specs:
MSI K9N2 Platinum Mobo (nForce 750a)
4gigs of ram
Windows XP 32-bit SP3
AMD 6000+ 3.1ghz Dual Core Processor
MSI SLI Bridge (Came with the mobo)
GeForce XFX 8600GTx2 (The newer one is actually an overclocked version by XFX, but not by much)
I am using the latest (181.22) drivers.
The problem I have only seems to occur at 1680x1050 resolutions and higher. When I have SLI with SFR enabled, the top half the the screen is fine, but the bottom half has a lot of what seems to look like tearing and distortion. On AFR mode, it's almost all over the screen except the right most side about 1 inch away from the edge of the screen. This lead me to believe that maybe the card I got was bad, but I tested each card individually in each slot and they both ran just fine by themselves. When I turn down the resolution, the screen problems go away and the game seems to play just fine but the FPS tends to be jumpy (but stays over 25fps, this is while playing WoW with all the settings turned up except shadows).
I recently tried to use the nHancer tool to try to single out the problem, but I only ran into more questions. Whenever I ran the game in the wow profile, i would get the same problems unless I turned SLI mode on single (off). But, whenever it was on global profile setting, which was set to SLI mode of Auto, I would be able to run the game at 1680x1050 with no screen anomalies at all, with the fps as high as 180+ in closed in areas and as low as 20-30 in areas like Dalaran. But, whenever I turn on shadows to max, the game locks up completely. I am able to alt tab and force the game to close. Also, whenever I put the SLI mode on anything but Auto or single, I go back to having the same problems.
The nature of this problem makes me believe it to be the process in which the cards are communicating to each other, as in SLI SFR, the top screen is fine, but the bottom is distorted, and in AFR (although i cannot see with the naked eye) I could assume that every odd frame being rendered by the master card is coming out fine, but every even number is getting corrupt. Are there any previous nvidia drivers that may resolve this issue?
I've read that some people resolve these problems entirely (with a minor fps hit) by removing the SLI bridge. Would this be an option?
Whenever I use the global settings in nHancer, it does not seem as if my game is utilizing SLI as the FPS stays in the low 20s and 30s for maybe 20 to 30 seconds, and then the FPS picks up to 80+ regularly as if it is working. I assume this just to be the time for everything to load/be rendered, but confirmation would help.