Just spotted this bit of Info over at 3DChipset.com.

Recevied word from Josh Walrath over at Penstar Systems that he has ran into some problems with Athlon 64 Gigabyte motherboards. The problem he is having sounds awfully familiar to the intro of the Radeon 9700 Pro with crashes. I've had the same problem he is having. What's even more ironic is that I was on a Gigabyte board as well. It was the i850E Rambus board though. Note to myself, "If you own a ATi card, stay away from Gigabyte".