Quote from: UberDaemon on June 17, 2017, 04:41:02 AM

Quote from: jimmykl on June 17, 2017, 02:02:22 AM

Quote from: UberDaemon on June 16, 2017, 08:04:19 PM

So my 2nd rig is now running with 6 GPUs.

Why are you running 7x cards on a single psu and 6x on the dual psu config? From your 'at the wall' readings I would think 1200W would be ok for each rig? Is there a reason why you went dual? Asking as I'm planning on running similar rigs myself with a single 1200W supply.

I'm running 2 PSUs on rig 2 because these EVGA FTW cards have (2) 8-pin PCI-E input ports on each card and the rig won't boot unless both 8-pin PCI-E input power slots are populated even though I'm only using 125W per card. My Corsair PSUs only have 6 "type 3" PCI-E 8-pin outputs, and you have to use one of those outputs for the CPU/motherboard, which leaves me with 5 "type 3" 8-pin PCI-E ports to power GPUs on each Corsair PSU. On rig 1 I have 3 GPUs with a single 8-pin PCI-E cable running from PSU->GPU, and the other 4 GPUs are running 1 cable > 6+2 PCI-E + 6+2 pigtail (so one cable per 2 GPUs for those 2 pairs of graphics cards).

The "at the wall" readings are a bit high on rig 1. The conventional wisdom is to only use 75% of a PSU's total wattage if you're going to be running it 24/7. That means for a 1200W PSU I should only be running 900W, but I am slightly over that threshold on rig 1 (945W). Since it's a platinum rated PSU I'm not too worried about pushing the limit somewhat, and I have checked and triple-checked touching those 8-pin cables to see if they're warm to the touch and they never are. If I wasn't using platinum rated Corsair PSUs I would not exceed 75%. If the cables were warm (or hot) I would back off as that would signify they're moving too much current for the internal conducting copper to properly handle, but Corsair makes a great product and I think their PSUs and cables can withstand what I am expecting out of them.

Excellent thanks for those details. I'm going to be using Corsair AX1200i's (platinum rated) and glad to hear they are good quality. By my calcs I should be around 88% utilisation. Will definitely be keeping tabs on the cable temps by touch and infrared thermometer once they're up and running.