Just putting a note on here to hopefully help others that might run into the same issue.

Got an issue with my PC at the moment with high sub system latency causing audio issues (but that's for another thread).

So was going to start with making sure I was on latest bios and had latest drivers etc so flashed the mobo bios to 5701 from 5404.

Although the flash was successful the gfx card would not initialise at all, with Default settings or otherwise. Thankfully the motherboard has an on-board VGA so I was able to hook this up and get to BIOS and even windows but the gfx card would not work.

After spending 10+ hours meticulously changing BIOS settings, trying different PCI-E slots, clear CMOS I just could not get the gfx card to work.

Thankfully due to the on-board VGA I was able to flash the motherboard back to 5404 and after a clear CMOS the gfx card was working again.

I can't tell what changed between 5404 to 5701 that could have affected this or even if the issue is 5701 as there are a couple of other bios revisions in between but I don't think I will update the bios again for a good while!