If you have 275.33 you already have the latest profile. Nvidia updater software automatically download it. But Witcher 2 profile is the same as older releases like 270.61, so it doesn't improve performance. Witcher 2 sli performance right now is good enough to play at 1920x1080 maxed without ubersampling with constant 60fps. But having two gtx580 in sli to play at 1080p is a waste. We need an optimised profile to squeeze the card's potential and able to play at higher resolutions with acceptable framerate.