Themperror

Few I can think of: Serious Sam 3 support up to 4 I believe (even multi-keyboard/mouse setups) Dungeon Defenders supports up to 4 Trine 1 and 2 up to 3 I believe (not sure) Magicka supports 4 players Racing games generally have support for up to 4 (Though I'm not sure about any latest ones (been a long time since I played those)) more here: Co-Optimus - Your Prime Source for Co-Op Gaming - Listing of PC Co-Op Games set the filter player count to 4 and select Split_Screen or Couch Co-op

I'd say probably yes, but only in games were the timer hasn't been set lower already, I would assume Unreal Engine already does this to max performance so that would rule out and Unreal Engine games (Though this is only a thought, not a fact). Feel free to try though, It won't break anything and you could report this back to us. See it as a little experiment

I can't even run it with 2x 560ti SLI and a Phenom II x6 processor without getting less then 30 FPS and severe laggspikes at moments (2-4 fps) I've waiting since launch to get a decent patch that will fix most problems.. And to everyone else in this thread, Watch dogs on PC has alot of problems and is a bad port as said by many of previous repliers. You can try mods to help improve you experience a bit, but don't expect too much

Diablo 3 had issues with Nvidia Optimus around the first few launch-patches, It might have returned, check the Blizzard forums for more support, else try running the game with the Onboard GPU and see if it changes anything (or Force running the game with IGP or GPU from nvidia control panel), this might be a more long term solution then updating your audio drivers (which is weird if it would fix that)