Temperamental fan on graphics card

I have an Asus ATI Radeon AX800XT card, which was recently replaced as the previous one kept over heating and crashing on games.

This one has now started doing the same thing, and I've realised why; the fan on the card isn't always on. It's usually on when I first turn on my pc, and then about 5/10 minutes into playing a game it crashes, and the fan has stopped.

This was a £350 graphics card, so you'd think it's a bit of a coincidence that 2 of them were just faulty and the fans stopped. Is there any chance that the mobo or the power supply (or anything else?!) is conflicting or causing this?

Nothing in my system is or has ever been overclocked.

you could RMA again or buy a decent aftermarket cooler, stock fans aren't usually great but they shouldn't be dying! not got a VERY dusty pc have you?

I smell VF700.. or AC Cooling

Nope, it's not too dusty.

I'd be happy enough to buy the VF700 if I was sure it was just a dodgy fan, and not something else that's causes the fan to stop... hmmm, dunno what to do.

What's AC cooling?

AC Silencer..