4 7970s on one HCP-1200 power supply - safe or too many watts?

[tyz007]

I am running 4 7970s on one 890FXA-GD70 board with one HCP-1200 PS.  Using BAMT and cgminer, and really the hashrates aren't that great.  About 630 m/h at 1200 core/1050 memory.  I'd like to see them get closer to 680 each, but I'm not sure what else to try short of diablo to get them up, and bamt isn't really set up for that.  However, that's not really the main point of this post.  

My main question is -- is it a bad idea to run 4 of these cards on on one Antec HCP-1200 PS?  The PS is a 1200W, and I'm running pretty close to that.  Killawat bounces between 1060ish and 1140.  I'm not super excited about running the PS so close to the max, but it's a solid PS, so it should be able to handle it.  If I could undervolt better in linux, this problem would be solved, but I don't think there's a way to undervolt 7970s yet in linux.

Does anyone have any opinions on whether it's ok to run all 4 of these cards on the one power supply, close to the max?  Safety is really my first concern, as I don't want anything to ignite.

[multi#lord]

hmm I am assuming you are using air cooling for those cards? I have a pair of 7970s on water at 1225 MHz each (~39 C), combined they put out on average 1464 MH/s (~732 MH/s each). I think 630 MH/s is far too low for the level of power consumption you are experiencing; it should not be a problem to run all four cards on the same power supply. If you arun at 1200 watts or more for a while, then the psu will lose some of its life.

[tyz007]

Yes, air cooling.  I think the hashrate is too low also, but that seems to be the best I can get with BAMT/cgminer.  Not sure why it's so low.  It's annoying especially at the higher power consumption.  Hopefully BAMT will improve 7970 support soon.  I could just run it on ubuntu, but I like running everything on BAMT for the monitoring.

[cwerdna]

I don't know the answer to this but you are running fairly close to capacity of the PSU - assuming that it is not overheating and under warranty you are technically within specification. However how much longer than the warranty period do you want the psu to last? I am guessing that even a decent quality PSU is possibly not designed to run at 95% capacity 24x7 indefinitely?

Something else to consider - if your PSU does die how much will your downtime cost you in lost mining time? :-)

[tyz007]

These are good points, but I am using a HCP-1200.  From what I understand, this power supply is designed to run pretty close to peak capacity for extended times.  I wish I could undervolt to get the power usage down a bit, but I really don't want to run windows, and linux doesn't seem to be able to undervolt 7970s yet.