I already tried two different brand ones... the original, and one I got as an RMA replacement since they were out of stock (original was XFX which ran out, so they had me re-order an Asus version). I just didn't have much luck with the 5870 cards.
I have no issue with all my 5870s and 5970 ..
its either you have a bad card or something in your system that have conflict with..
while it happens on you but not on majority, that mean there is something going on with your system....