Overheating issues with 6600gt

I just got a Chaintech 6600gt and it was working fine for a few days, then suddenly it starting doing the polygons that stretch across the screen and crashing deal as described in another thread. I enabled the temperature monitor in the firmware, and it was doing 60 deg idle and 90+ deg under load...that has to be too hot. This is with stock speeds, by the way. So I attempted to clean the heatsink/core and apply arctic silver...and now temperatures are even worse. It was the first time I've messed with thermal compound and I think I must have messed it up.

I've also noticed that the heatsink cools both the core and the bridge chip for AGP, and the bridge chip has some sort of thermal pad. Maybe I should take that off and apply AS there as well? I'm theorizing that maybe the heatsink isn't fully contacting the core. Also, the heatsink has a really crappy surface with a clearly visible grain. Are there any aftermarket coolers that work well with a chaintech 6600gt agp? Will that fix my problem?

60 at idle is normal, 90+ under load is slightly higher, mine is about 85 when it was using the stock heatsink.

The core of the 6600GT is quite large so you need to make sure you put enough arctic silver on it.

Just stick a different heatsink on it eg. Zalman VF700

Are those temperature enough to cause artifacting? And can overheating be caused by an inadequate power supply?

Remember that if you change the hsf you will need to put a cooler on the bridge chip, zalamn make both
http://www.scan.co.uk/Products/Produ...oductID=168309
the above is an excellent cooler and
http://www.overclock.co.uk/product.p...t=389&view=rel
is for the bridge chip.