Ok i think that maybe im wrong.. but he just want to play assassins creed with good graphics and smoothly.. what you have to do is buy a new video card. Your actual video card can't play AC in high graphic settings, so forget about OC. Just buy a new videocard. i think that an ati 4830 would do it. Or if you like geforce well an 9800gt would be ok. So please stop posting about OC since that is not the issue. Even if his quad reach 4.5ghz he won't be able to max the game.
PD: i had also sync problems when playing AC. In battles, sword sounds were out of sync even with good framerate.
PD2: My english is awful
