Seems to be mixed. Personally, I have two GTX 680s 4gb in SLI, and I've had nothing but issues with the PC version. I get a lot of screen tearing, and FPS drops. I ended up jumping over to X1 (which also runs poorly, but is more consistent). I'm willing to chalk this up to, driver issues. Or some incompatibility with my rig. Others have lesser Nvidia Cards and have said they aren't having any issues. Strange enough, I can run Crysis 3 and Battlefield 4 at 1600p with no issues at all (Ultra settings). But Titanfall is just crippled on my computer. *shrugs*
What AA settings are you using in nvidia inspector? I used
this nvidia inspector profile which was uploaded on the official nvidia forums as a baseline and started experimenting. Try these settings (don't have to use the profile):
SLI compatibility bits (DX1x): 0x000000F5
Power managment mode: Prefer maximum performance
Vertical Sync: Force off
Number of GPUs to use on SLI rendering mode: SLI_GPU_COUNT_TWO
NVIDIA predefined number of GPUs to use on SLI rendering mode on DirectX 10: SLI_PREDEFINED_GPU_COUNT_DX10_TWO
NVIDIA predefined SLI mode on DirectX 10: SLI_PREDEFINED_MODE_DX10_FORCE_SFR
SLI rendering mode: SLI_RENDERING_MODE_FORCE_SFR
Most of the settings are from the uploaded profile, but it used the SLI compatibility bit from half-life 2: episode one which was entered in the dx9 sli compatibility field (the game runs in dx11?). Anti-aliasing was messed up (or absent?) with these settings, so I entered the compatibility bit from call of duty: ghosts instead and placed it in the dx11 field. Also seemed to result in better performance.
Regarding the SLI settings (the verbose part), only SFR works without graphical bugs and crappy performance for me. Afr and afr2 leads to weird screen flashes which are very disorienting in-game. I think the issue with only entering the ghost compatibility bit in nvidia inspector is that afr or afr2 rendering modes are autoselected.
The power managment mode setting and the gpu count setting are probably unnecessary (lifted from the uploaded profile), but I didn't have the energy to test without them. Vsync off is a personal choice, because I am running 120hz.
In the end I think the performance is good now. Fps is 120 or higher a lot of the time, but there are some drops to 85-90 or so when things get hectic.
System: 3570k @ 4.4, 8 gigs ram, geforce 780 sli x 2, win7 64 bit.
Game settings: 1080p, texture detail very high, msaax4, vsync enabled (to disable 60 fps lock), everything else maxed
I hope this can help some people.