Ok. Now before anyone starts flaming me, i'm just posting this for those of us forumers that haven't heard of it or are looking for a fix for this issue. I'm just trying to help.
Basically Windows has a bug that hasn't been fixed...Ever...
It's a problem for gamers when it comes to FULL SCREEN REFRESH RATES. Windows by default will adjust your refresh rate to 60MHz while using full screen appz/games. This is a real pain in the butt for gamers because 60Mhz refresh in new games really sucks. Regardless of what videocard you have, you will experience slight studders in display. Kinda like the picture is wavy... sort of, it's hard to explain. I was having this problem with a PC with a X800XT PE only with some games.
Now there are a few other ways to tweak windows, directX or use RivaTuner but, this program is awesome. Works Great.
It's called RefreshForce. Download it here: http://www.majorgeeks.com/download.php?det=1847
After installing it and adjusting the refresh rates at different resolutions, the isue that I described is gone. Also I ran a quick Aquamark3 Bench and I actually was able to gain 800 more points.
I ran it again 2 more times and got the same score.
IF this could help someone good. If not... Sorry for wasting my time.