XFX 7800 GTX SLI Issue Vista 64bit - Device encounters problem

[AndersSchm]

Reposting as put in wrong forum initially.

Using driver release 175.16 I have a pair of XFX 7800 GTX's running an SLI configuration in 64 bit Vista. Generally they work fine but sometimes they will fail to initialise on boot and both display yellow exclamation marks in Device Manager reporting "the device encountered a problem so has been disabled".

A reboot is normally enough to fix this issue however I want to understand what is happening.

Both cards are running stable at around 70C so that isn't an issue.

If I use the base drivers with Vista 64 bit I don't have the issue but can't SLI or get anything much good out of the cards! I find older drivers (158.18 and 169.25) give me a blank screen when turning on SLI requiring me to power down and come back in safe mode.

[AndersSchm]

Finding that XP is having the same problem so it likely isn't software related.

How can I diagnose HW or should I just send both cards back to XFX?

[XFX Tech]

The best thing to do would be to try each card individually, individually in another system would be best. Isolating the card from anything that could cause a problem in your system and then further from each other should show whether it is a hardware problem or not. To have two cards go bad at all much less at the same time is playing same very low odds so this is the best route for diagnosing the problem.