nV 6800GT AGP - odd flashing squares...

[Mutley]

I have a Club3D nVidia 6800GT AGP (256MB RAM). Good card, and it has served me well. Just the other day, something odd started happening. It *some* games, either when viewing splash screens or in game, you see a series of flashing squares, like sprites, across the screen. The squares are just made of a few horizontal lines. They don't stop the game working, and are more an annoyance than anything else.

This happens in DoD: Source, and in GTA:Vice City. In DoD:Source, the aiming site gets garbled...It doesn't happen in other games though, such as Battlefield 2142, and Need for speed Underground 2.

I've played with various graphics settings, and the only thing that makes a difference is forcing the anti-aliasing setting. If I set this to 4x or above, the problem goes away (with an obvious performance impact). Any lower setting, and the problem remains.

I'm using the latest nVidia drivers, and the card is not OC'd.

Any ideas?

Mut.

[sTrAnGeFrUiT!]

is the card overheating??

i had a recent issue with mine were the fan stopped working without me relizing

[kalniel]

Do try a small underclock to see if it helps.

Do you know if the problem started when you changed drivers, or has it started without you changing anything software wise?

[Mutley]

The card isn't overheating, checked that. I removed, cleaned and reseated the card as well.
I also tried underclocking the card to see if that helped, but it didn't.

The problem seemed to start spontaneously, which would suggest a hardware issue. But what i don't understand is why only some games are effected, and why sticking on 4x of AA fixes the issue...!

I also play with Auran Trainz on occasion, which allows you to select DirectX or OpenGL. If you select DX, you can the same problem, if you select OGL, the problem goes away.

I've re-installed DirectX 9c as well, just to make sure.

Mut.