Graphics card causing endless reboot loop

[berry120]

I decided to upgrade my ageing Radeon X1600 and grab a HD6770, but after installing it the computer boots up, waits a few seconds then powers off for a few (usually powers on for around 3 seconds or so but it can vary!) It then powers on again and the cycle repeats.

Any ideas? Originally I thought the power supply was likely not beefy enough, but after trying two others that are more than powerful enough I get the exact same symptoms, so I'm pretty sure it's not that. Equally I wondered whether the card was dead, but in a friend's system it works fine.

I'm left with the motherboard, a G41M-LE - but it's running the latest BIOS and I'm not sure what settings I could change in the BIOS to fix it! (Restoring the default settings didn't work.) It may well be running an older version of PCI-E but I thought they were meant to be backwards compatible?

[IAntDemo]

try giving the cmos battery a reset..

[berry120]

Already tried that one!

[IAntDemo]

did you install the update for bios yourself? Or was it already done when you bought it

[berry120]

Installed it myself - same behaviour before and after though. It definitely updated ok however

[IAntDemo]

maybe it's that? I'm guessing it is... I'd advice go back to the default and retry if not then atleast we are degrading it down to certain things

[berry120]

I mean it was at the default BIOS, it didn't work and I updated to the latest version after it didn't work but had the same behaviour afterwards.

[celegorm]

See if your BIOS has any memory sharing with video cards and disable if possible. It could be some weird issue where the BIOS can't allocate memory properly.

[berry120]

It does for the onboard graphics but those options disappear when the PCI express card is selected as the primary card - either way I get exactly the same symptoms though whatever one is set to primary (on-board, PCI or PCI express).