Dual 5970s killing PSU

[PinkBatman]

Hello all I will start with my system.

XION XON-1000P14F
GIGABYTE GA-990FXA-UD3
AMD Phenom II 925 (stock clock)
2x4gb G.Skill DDR3 1066 Ram
2x AMD 5970
1 2.5" Sata HDD
Open air case
Win7
Phoenix miner

GPU:
Voltage: 1.135
Shader: 920
Memory: 500

I am still using Afterburner, I tried CG miner but it was very unstable and about 10% slower than phoenix.

When I first built the system I was running a single 5970 with great results. I purchased another just a few days later and install it, after an hour it goes down, PSU wont power. I send the PSU back to Newegg. In the meantime I put the two cards into a video editing machine that gets little use, the PSU is a Rosewill 750w and put a Kill-A-Watt in line this time. At the wall this system drew ~950w, but was stable so I let it run while I waited for my Newegg return.

Today I got my replacement 1000w, got everything set up again, and turned it on (about 1005w at the wall). Everything was running great, I watched it for about 15 minutes and temps were stable so I left it to work its magic. Come back and it's powered down, tap the power switch to reboot it and see a large white arc in the PSU.

So I'm wondering whats the best thing to do from here. The eXtreme Power Supply Calculator says the system should only be using around 550w, where is all the extra power coming from? I cant imagine a PSU is only about 55% efficient, does OCing the GPUs add much extra wattage?. Maybe I need a name brand PSU?

Any help would be appreciated, I've only been doing this stuff for a few weeks.

Thanks for the help.

[vmarchuk]

Look you maybe got bad power supply. I have 5970 and 6990 in one rig and draw 828watt on 1000w power supply. I not overvolt. Remember, 1000W listed not 1000W useable !!! If you overclock both card running 920mzh with overvolt, you playing with fire.

[PinkBatman]

Whay kind of hash rates do you get on the 5970? Before this psu problem I was getting 410 per gpu.

I just did some tweaking and am now at 850w at the wall. I'm losing about 60mhash per gpu now though. Might be worth it to go to a bigger psu.

[DILLIGAF]

Whay kind of hash rates do you get on the 5970? Before this psu problem I was getting 410 per gpu.

I just did some tweaking and am now at 850w at the wall. I'm losing about 60mhash per gpu now though. Might be worth it to go to a bigger psu.

Either that or buy a quality name brand PS from the likes of Corsair, Seasonic, Antec... Single rail with high amps on that rail, Active PFC, 80% + certified not some no-name multi-rail (six god damn 12v rails FFS) like that thing is then he just might have chance in hell of a 1000w actually running the rig.

http://www.newegg.com/Product/Product.aspx?Item=N82E16817190030

[PatrickHarnett]

I recommend you get a decent PSU.

I have a preference for Corsair PSUs, and I have had a faulty TX950 (replaced via RMA), and also a cable that was wired wrong at factory.  However, I run 3x5970 on an HX1000 with no trouble.

Current stock is 2 HX1000, 2 HX850, 1 HX750, 2 TX950 and a bunch of other lower rated thermaltake things that don't run as well.  The HX850 is fine for 2X5970.  Only one PSU I've had went "bang" properly for no good reason (I think it was a 550 something on a low powered rig) and that was straight into the trash.

[jake262144]

Just exactly which model did you have, the LIGHTNING-1000 or RBR1000-M?
Perhaps the white arc you saw was just a lightning bolt and everything is in order?
The RBR1000-M is a multi-rail design, you might have botched the load topology - then again, if the protective circuitry worked as advertised the PSU should have shut itself down to prevent a failure.

1005W at the wall translates to ±820W on the DC side of the PSU so you should have been reasonably safe.
You definitely didn't overload the PSU unless the CPU got highly loaded when you were gone and required much more power. Frankly speaking, Windows is perfectly capable of doing that.
You may have gotten a flawed PSU this time, do remember that the 750W model worked fine even though it was slightly overloaded (with 950W on the AC side, the estimated DC load is again 800-ish).

Truth be told, you're pushing those 5970s very hard. When you overvolt a card, the power consumption rises proportionally to delta voltage squared.
I don't think I've seen any 5970 draw more than 280W... ask DAT, he has a small farm of 5970 cards.

Make sure you enabled all CPU power savings options in the BIOS (AMD cool'n'quiet and C1E) and that you don't use a flawed driver version resulting in totally unnecessary high CPU load when mining.

Vmarchuk is correct, you don't usually want to push the PSU further than 80..90% of its rated maximum continuous load but keep in mind that the actual PSU load should be measured on the DC side. When the best you can do is measure at the wall you need to multiply the readout by the efficiency factor∈(0, 1] which should be at least 0.82 for a bronze-certified PSU.

Pay no heed to that online power calculator, mining is a totally different animal than gaming or any other typical PC use pattern. Trust only your kill-a-watt.


When in doubt choose Seasonic PSUs - their 7 year warranty period is a fine testament to high quality design and manufacturing.
A manufacturer can't cut corners and expect their product to work flawlessly for seven years.

[PinkBatman]

So it looks like a new PSU is the only way to go. Thanks guys, this forum is a true asset to Bitcoin's future success.

@DILLIGAF

Thanks, that looks like a great list of things to look for in a PSU, much better than the random selection I made last time.

@PatrickHarnett

What are you running the 3 cards at for clocks with a 1000w PSU?

@jake262144

Thanks for all the efficiency numbers.

CPU power savings isn't something I had looked at yet (or thought about) so I will be checking that out when I get the rig running again.

[PatrickHarnett]

@PatrickHarnett

What are you running the 3 cards at for clocks with a 1000w PSU?

I don't run high clocks, so just stock on that one 725/500 - runs nicely at 1.8-1.9Ghash.  I did experiment running 800/500, but having 2.3Gh wasn't worth the risk of a failure in my view.  I have another dual card box running 775/500 at 1.3, but the gain isn't very high.  I have been using GPUs 24/7 for a year before I got into bitcoin so want them to last, rather than fail.  A bin of dead 5970's is expensive.

At some stage I will look at the sub-300 mem clock speeds and changing the work size from 128 to 256, but that's still low priority.

[DILLIGAF]

So it looks like a new PSU is the only way to go. Thanks guys, this forum is a true asset to Bitcoin's future success.

@DILLIGAF

Thanks, that looks like a great list of things to look for in a PSU, much better than the random selection I made last time.

Oh yeah that is the list you want when buying and remember capacitors age with use so that 1000w new PS is not going to be putting out 1000w next year or even six months later so always go a 100 or 200w higher than you need to have room for that aging as extra added to the supply. Also while in the BIOS as was suggested turning on the power saving turn off things like the audio, com and parallel ports extra nic if the board has one in short if your not using it turn it off ever bit saved helps.

[jake262144]

Oh yeah that is the list you want when buying and remember capacitors age with use so that 1000w new PS is not going to be putting out 1000w next year or even six months later.

I beg to differ.

Correct voltage levels are being maintained by a supervisor circuit and I can pretty much guarantee that they won't change in a year.
The maximum achievable current depends mostly on rectifying bridges and mosfets. They won't degrade within a year or two unless you seriously overload them, and protective circuitry should preclude you from doing so. If the PSU feels it's in trouble, it'll just power down.

Worn out capacitors will result in increased ripple and noise (electrical noise, not audible noise) but that won't happen within a one (or even two) year timeframe.
Capacitors are used for filtering only and by themselves have nothing to do with voltage levels or maximum current.

Maintaining a 200W buffer space is a very prudent approach, except not for the reasons you specified.

[PinkBatman]

Wow, I'm learning a lot from this. Thanks a ton guys.

I just setup a refund for the second PSU, Newegg waived the 15% restocking fee for me . Got a 910w single rail with Active PFC and SILVER certified ordered just now (7 year warranty!).