I've had my 5870 for several weeks now. From day 1, I would get a big cursor problem and also the screens would flicker whenever its power states changed (i.e. Idle, 2D, 3D).
I started out with 9.11 drivers. Later on, I started getting random BSOD with ATIKMDAG.sys - those BSODs usually appeared when the PC was idle actually.
Later on, those included blank black screens without any cursor or Ctrl + Alt + Del response. I couldn't even reach Windows login!
I've attempted the following troubleshooting with my 5870 Vapor-X:
9.10, 9.11, 9.12. 9.12 Hotfix drivers - no effect
Format & re-install Windows - no effect
Try different PSU - no effect
Try different PCI-E slot - no effect
Try underclocking the card - no effect
Try running my CPU, RAM, etc at stock - no effect
Try underclocking my CPU, RAM, etc - no effect
Try running only 1 monitor - no effect
Today I'll try the card in another machine which is AMD based but I suspect I'll get the same problems. Even if I don't, I will RMA the 5870 because most importantly the card does not work in my INTENDED machine, so WTF?!
I've read extensively online and bricked 5800-series (and some 5700-series) cards is a VERY common problem now regardless of brand or factory-OC or cooling. I will initiate the RMA process with Sapphire on Monday. I have no choice!