Using 10.8 drivers here. 5870 card. Nemas problemas.
Snacko, how do you uninstall drivers before you install new ones? There's a rather thorough way of doing it to make absolutely sure you have gotten rid of the old drivers. Some people will say that it isn't necessary but sometimes it can help because on some occations, the installer won't completely remove the old ones. Here's what I do:
1. Download new drivers
2. Uninstall old drivers in Windows.
3. Restart computer and enable windows safe mode(tap F8 at POST screen).
4. Use Driver Sweeper(Google it) to remove the drivers in safe mode
5. Reboot computer in normal mode and install new drivers.