Weird issue in every game (might have to do with RAM)

Hello

I've had this issue forever, it doesn't matter wether i'm playing on low or ultra. Details on the ground like rocks, lawn... Appear as i walk

I captured a video when playing bf3, its like the worst ive seen, normally it's appearing 5 meters in front of me

http://www.youtube.com/watch?v=On9f3Qif-SM

It's really really bad when playing Assassin's creed Brotherhood or Call of duty 4.

My system is

i5 750 2.67ghz with stock cooler
4GB of ddr3 1333 noname brand
GTX 680 EVGA superclocked
Asus p7p55d-le
Vertex 3 120gb connected in sata 2
power supply 600w noname brand
Windows 8 64 bit pro (it doesn't have to do with that I'm sure of it)

Thank you all