stuttering in games with high FPS

[hercules71185]

I know I've posted a lot lately but, I have numerous un-answered questions that google isn't being too friendly with.
I'm having stutters in games even when my FPS is around 100, then if I turn on Vsync, I still get tears in my video. It's definitely not a ram issue. I ran memtest, overclocked the hell out of it and then put it back to stock. It's pc2 8000 and it's running at 6400 speeds. Right now due to my mild overclock it's at pc2 8000 speeds exactly. Memtest says no errors, when I ran the memory tool in vista same thing no problems.
So the last thing I'll do is give you an example and hardware.
A simple game like UT3 FPS is dead on 60FPS-62FPS with vsync on a 60hz screen. Never drops. Yet when I turn around the screen has a wave split in it.
Sims 3(my gfs game) it doesn't both her, but the game stutters like nothing else, it constantly loads textures instead of using my ram. Oblivion, loads every 30ft and pauses to a 10FPS lag then back up to vsync, even with vsync and AA turned off all these games are doing this. Is this a ram issue? Having 4GB in 32bit bad? Or is some weird setting off.

Hardware
E5200@ a mild 3.1
2x2GB DDR2 1066 by OCZ platinum
EAH HD 4870 512mb dark knight edition
and the sigma shark psu. 635 watt (very solid PSU from reviews)

[InspectahACE]

I know that if you're using Vista that sometimes even forcing the Vsync on won't actually do it. a good portion of the time, leaving it to App Controlled(however ATI does it) fixes it. That's on an nvidia card though . Worth a shot if your card has that option