There is two different problems: with SLI and with Surround. Both decrease PA performance dramatically.
Actually, are the 560ti's 1GB cards or 2gb? If they're 1gb, I think I know what the problem is, and it may have nothing to do with SLI (though you should probably disable regardless for debugging). run GPU-z with the game running and see how much of your video card memory you're using when it starts to slow down.
I will certainly do that sir..... Yes their 1GB cards and if its down to VRAM usage I'm screwed haha, cannot afford new cards right now EDIT: Yep my VRAM gets almost entirely maxed out but doens't go above 1003GB though, usually holds around 983MB out of the 1024MB of VRAM on the GTX 560 ti. One thing I did notice, it doesn't clear the VRAM when I finish, it was still using 980MB at the main menu, I had to quit out of PA in order to clear it...... It only got chopping when I went passed the 900MB, and the SLI almost entirely fixed every slowdown I had...
It's known problem: FS#74 This issue is about RAM usage, but I'm also noticed that PA doesn't clear VRAM too, but I'm personally don't sure if this might affect performance because VRAM work by different way.
Yeah not sure either but Garat wanted that info so I posted my findings... It didn't really slow me down terribly but definitely noticed the performance difference though... Biggest FPS killer for me tho was the Sli issue
Yah, and it's one we're actively working on, today actually. We had texture compression disabled for a while, and we're working on bringing on the fly compression and caching back, which should minimize the amount video cards need to ever page to the system memory. Hopefully never, but I'm realistic about it.
