Z77-D3H & OCZ ZS 650w weirdness

[tommm]

Out of the blue my week old build stopped booting, no fan / lights or anything, after re seating everything and clearing cmos / trying a minimal config etc I still had no luck. Tried old Seasonic 500w and it booted first time and is still going strong a week later, but now I've got round to trying the OCZ PSU in an old computer before RMA and typically it boots fine.

Google reveals some issues people were having with this board where it takes around 15minutes after a complete power drain (cable out, hold power button, reconnect) before it would ever boot back up and now I'm wondering if this is what could've been clouding my debug process with the PSU? I was frequently unplugging when moving the comp to test various configurations so it could be a similar issue complicating things?

I guess it is also possible that there's just something strange that the mobo doesn't like about the PSU, although it had been running flawlessly for a week or so prior to the issue. I'm guessing I'll have to try the OCZ PSU back in this machine again but I'm sick of faffing about with it at the moment!

I'm running the latest BIOS F13 since day one.

Spec is:

Ivy 3750K
Z77-D3H
8gb Corsair Vengence
Sapphire 7850 2gb
128gb Corsair M4
500gb WD Hdd
OCZ 650W(grr) / Seasonic 500w

[wazza300]

could be faulty psu,even if it worked on another motherboard,ive also seen a few users have trouble with ocz psu's and gigabyte boards,this was back on the x58 boards,just an odd incompatibility issue,idk if its still happening on z77

[tommm]

I've heard a few things about not having enough load on the 12v line for the PSU to boot, might try stick a few extra fans on to the molex connectors as a test with the problematic PSU. Strange how it would happen all of a sudden though with no changes...

Also there is F14 bios to try, but not sure it lists any relevant changes.

[wazza300]

its hard to say for sure whether its a bios issue or psu incompatibility,just test with the ocz one again and see how it goes with f14 bios

[tommm]

Think I've narrowed it down to using the displayport on gfx card, once anything is plugged into it, there's no boot! I believe there is some weird luck combo of clearing cmos and plugging gfx / power in that can get it to occasionally work, but with cmos cleared and using DVI it's now OK.

How strange?

[wazza300]

yes,does seem strange,maybe bios bug

[tommm]

Apparently there's an issue with non-spec DisplayPort cables that have pin 20 incorrectly connected meaning power actually flows from monitor to gfx card when it's plugged in, hence all the weird power symptoms. There's a fair bit on google about it, if only I'd figured it earlier!