Whats wrong with my GPU?

[666_Pounder]

Nearly a month ago now I noticed a a drastic change in my 3D performance on my PowerColor HD4870 1GB, in short, pop up, everywhere.

I everything I never had pop up before in things like TF2, Fallout 3, Far Cry 2 etc, its actually worst in COD4, every step I take brings trees, building, textures, shadows, you name it ... It pops up.

Its not my CPU as my new Q9550 arrived today and its exactly the same, its not the powersupply, that was recently changed to a OCZ ModXStream 780w, its not the motherboard, again recently changed to a P5Q-E and its not the RAM as all my sticks show the same results. Not the HDDs either as I borrowed one from someone and again, not a sausage difference.

So, whats it likely to be? I'm going to try and RMA it anyway so I can sell it on but I'd like to try and find out whats up with it.

 

[666_Pounder]

Yeah, um, like textures and shadows all appearing as I move forward instead of being there already, I can see objects in the distance but details etc all pop into place as I get close to them. I'll try and find a video or take one using xfire.

 

[666_Pounder]

Its this -

http://www.youtube.com/watch?v=T857VIjgDU4&feature=related

Only on a much closer distance, I don't find that my FPS is much if any lower than it used to be though.

 

[666_Pounder]

ATITool doesn't open for me :/

GPU-Z reports an avg of 68 after playing TF2 for a while.

 

[666_Pounder]

Its set on 16x.

In checks out ok in SiSandra on all tests. Still no luck with ATITool but I'll have a reboot in a minute.

 

[666_Pounder]

I've tried every different driver I can find, I've reinstalled windows 2x and its always given me the same results no matter what I used.