Okey thanks for the answer guys, so I see it's pretty much just for getting it more stable, to squeese the few extra mhz as you say. that sounds pretty much what I was thinking to :)
About the gfx cards, yepp the first thing I was thinking about was the gfx card but nope it do not overheat/ or are to much overclocked so thats not the problem.
I think it must be the new games as Vorlon and I was talking about in another thread.
So I guess one have to live with it, it may be a thing called C-Fighting
Z-fighting - Wikipedia, the free encyclopedia
And these artifacts always shows up in the same spot in the games so it's pretty obvious that it's the way the game is rendered and not my hardware who fails!
Just dident think so much about this before but since upgraded my comp with all new stuff then i suddenly looking for every damn fault I can find LOL
BTW I upped to the great Corsair 1000W PSU when I bought my GTX 285 as the old PSU couldent handle my 8800GT for PhysX and GTX 285 together!