I spoke too soon, it's down again. But, I think I've figured it out.

I was watching as it happened. When claymore switched to mine for devfee, it couldn't connect at first, so the gpus weren't running at 100%. The second it connected and the gpus went to fire up, it died.

So it's something when the gpus turn off or go from 100% to 0%. Its the whole PSU that turns off. So I'm gonna order an add2psu and see if that does it.

And to make matters worse, I can't get sgminer to work since the fork yesterday. Got the updated cryptonight.cl file, but won't start at all.

Fuck.