Basically the problems are as you describe, terrible and inconsistent performance. Low frame rates when enemies appear.
The game just runs badly, although there is little consensus on whether the game or nVidia's drivers are at fault. There's a tendency to suggest that it's the game because AMD users are having similar issues.
In terms of the problems themselves, the SLI profile doesn't work properly, MSAA in game is broken and shadows result in excessive CPU load.
Various solutions have been found to help.
Load the custom SLI profile that's been knocking around (google it). Load it in NVInspector.
Disabling SLI results in more consistent, although not better performance.
Turn off in game MSAA and over-ride the game's anti-aliasing from within NV control panel.
Turn shadows down to medium.
Write to Ubi Soft and tell them that you don't appreciate them launching games with beta code.
@Marlonius What is your PC spec? Is't GPU limited system?
AMD FX4100 @ 4.4Ghz, 8GB DDR3 @ 1866, ASUS 7770Ghz @ 1120mhz Core & 1650mhz on the GDDR5, dont really need that program just thought I'd give it a whirl. I wasnt joking tho, it kills the image quality to achieve its supposed performance gains.. much better off dropping the resolution a bit and dropping post processing, shadow and object quality down, at least then you still have something half decent looking.
Have you done this: go into AFTERBURNER and enable the frame limiter at 60 FPS then ENABLE IN GAME VYSNC in game and its buttery smooth, this is what used to be done in Elder Scrolls Skyrim to get that to work perfectly.
Changing D3D11MultithreadedRendering="1" to D3D11MultithreadedRendering="0" in the GamerProfile.xml file
i bet this will help because it solve my issue gtx 770 sli i m getting constant 80-90 with stutter free