Bitcoin Forum

I am running 2 7970 graphics cards for litecoin and running an AMD FX 8 core processor using 7 cores for the primecoins.  I have a 750 watt powerpack.  This system is approx 3 months old.

The system was running fine just mining litecoins and bitcoin for a few months, and then I added the primecoin CPU usage and that ran fine for a week.

But now the system is just shutting down when I run litecoin on the GPU's.   PrimeCoin on it's own is fine, but run litecoin on the GPU's either on it's own or in conjunction with the primecoin and the system turns off.  Sometimes it turns of almost immediately, sometimes it runs a little while.   I have to turn it off and on again at the back of the computer to get it to restart.

It doesn't seem to be heat related as the system shut down pretty quick just running the GPU's (no primecoin) at approx 60 C.

I figure the Powerpack is dying?  But would appreciate any other opinions/advice.

What brand PSU?  Not all brands are equal. 

Try just with graphics cards and does it run fine?  If it does chances are you need a bigger PSU or dual PSU's

Gonna guess PSU. Post your specs. You might be overloading a rail or something.

Instant shutdown tells me one of two things:

CPU overheat - use a program like CoreTemp to check your cpu temps

PSU overload - overcurrent trip = instant off, cheap power supplies are a no-no if mining coins

The brand is "cooler master", model GX 750W Bronze.  It has a 5 year warranty.


Initially it was crashing on just the graphics cards alone.  But interestingly I just gave it a run on graphics cards only and it ran fine for 45 minutes, so I tried adding the cpu miner as well and it crashed immediately.

Thanks, I'll give it a go.  What sort of temps should I see if all is healthy?

http://www.newegg.com/Product/Product.aspx?Item=N82E16817171053

If you own this one, you "should" be pretty well set. The rail should be able to supply a maximum of 720watts (12v X 60a) to the video cards (each rated at 250w).

Depends on the CPU model. Post it. Typically, I'm guessing they aren't suppose to go much higher than 75'C. But some don't like going higher than 60'C, while others can go to 80'C. Depends on the model.

EDIT: My phenom 955 wasn't suppose to go much further than ~65'C, and would usually hang around 61'C. My new 1090t hangs around 40'C. But it's not suppose to go above 62'C

Just ran the CPU test.

GPU mining only sitting on 19 C

CPU mining only Sittting on 63C

Ran them both at the same time and it shut down almost instantly with no discernable CPU temp increase.

BTW the motherboard is a Gigabyte  990FXA-UD3

Well that's not right at all... typo, or is that what it's actually saying?

Also, try and get a kill-o-watt or something to measure the power draw from the outlet. Is the breaker blowing, or is it just the computer shutting down? You might not be supplying enough power from the wall and/or PSU.

It is just the computer shutting down.

Tested GPU mining again and that was still around 20C jumping up to max 25C

Yup, basically the same story for me. Then again, one mining rig that had this issue stopped having it and have now an uptime of several days. I have not had time too look into it.

Interesting, because mine has similar inconsistencies - for example it would not GPU mine at all (shutting down) but now it is GPU mining fine, only shuts down when I add CPU mining to the mix.

I read one brand of 7950 recommended (to run one card) 450 watts, whereas AMD/ATI recommended 500.

I had a 430 on one box and a 450 in another, and some recommendations only wanted 200 watts more to add a second 7950 so I figured I should have 230 watts on one machine and 250 on the other available to run everything other than the card. (If a second card needs 200 more doesn't the first card, presumably, being identical, only need 200?)

I put the brand new card in the 430 watt machine. Tried to start finding the settings for scrypt mining for it.

There was a flash and the machine shut down, and it won't start up anymore even without the card.

So I put it in the 450 watt machine. All looked fine until I started trying to find the right settings for scrypt mining. Each time it started to mine the machine shut down, but would start up again.

So I went out and got a 550 watt power supply. Tried replacing the 430, but that machine wouldn't start even with the 550 watt and without the card.

Replaced the 450, and been scrypt mining ever since. (And using the two core CPU with nice to primecoin-mine upon occassion.)

Moral of the story is maybe be glad your power supply was powerful enough to merely shut down gracefully, unlike my 430 watt one which seems to have left the machine itself traumatised in some way.

-MarkM-

If you plug a kill-o-watt you will see up to 380ish upwards on script depending on setting on each gpu.  As long as its like mine.   There are spikes and variances.  But with a I7, and fans, cpu heatsink, HD, etc... chances are you need bigger.   A kill-o-watt could confirm this though watch it once its mining see how close before adding in primecoin's.

Does this device measure what it is pulling from the wall connection?

If it is shutting down because it is drawing to much power from the wall supply, this would shut off all appliances connected there wouldn't it?  I ask this because I have another appliance connected at the same plug and it is not being affected.

Maybe we have some confusion there - I was referring to the CPU temp while running GPU mining.  The actual GPU's are running much hotter -  atm one runs at 85ish and the other at 67ish - I will be adding another fan to help the hotter card.

Turn down the speed or intensity on that 85° card.  It's running too hot.

85'C is a little hot IMHO. What gets me though is that you said in your OP that it only shuts down once you've started the Litecoin mining. What program are you using? Try using the newest version of Cgminer if you already aren't. You might have something improperly configured.

It's true that it was shutting down when I used the litecoin miner, but after making my original post it ran successfully on litecoin for 45 minutes, and so I tried adding the primecoin miner and it crashed.  I have since restarted litecoin and it has now been running 2 1/2 hours.    But I figure if I start primecoin it will crash again.  I plan to let it (litecoin) run overnight to see what happens.

I am using cgminer 3.3.1.

I am adding on a new fan for that hot card tomorrow so hope to see that problem rectified.

Here's my litecoin bat file:

You should be able to get away with running the gpu fans at 80. I've left my fans at 70 for the past two years, and they haven't died yet. For testing purposes, try running the fans at 80 with a small fan blowing on it. It should bring down the temps a few degrees.

Also, I remembered that the cgminer.conf file has temp overheat and cutoff options. They may have something to do with your computer shutting down.

Thanks, I will try this tomorrow when I get the additional fan.


Are you suggesting I add this to the config file I listed above?  ***edit***  I just re-edited my previous post - that is my bat file listed there.  I am not running it with the config file.  I am running it from the bat file.

Would two 9790 graphics cards draw more power than the AMD FX 8350 (8 core) when they are running to the max?

Definitely, the FX8350 is a 125W TDP CPU.

Did you mean a 7970? you're looking at ~210W TDP for each GPU.

Hey guys, I tested it from another power point that I know can handle a big power draw (use it for a projector), and we also tested with another (650w) power pack and it behaved the exact same way, so we think it is the CPU.

If you'd rather add those settings to your batch file, append this to the end of your cgminer line:


If you want to control the temperatures for the cards individually, you can use a comma-separated list as illustrated above (i.e. --temp-target 70,76).

As to your problems with the system shutting down, it certainly sounds like your power supply is the issue. The shutdown symptoms you describe are typical of a PSU's protection circuits shutting it down (this is a good thing actually... ultra-cheap PSUs usually don't have these protections and instead simply start on fire!). You mentioned your PSU is a Cooler Master GX-750. Typically, Cooler Master makes decent power supplies... but the GX-750 looks like it may be an exception. Check out this review: http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=188

The unit was unable to continuously deliver the full 720W on the 12V rail that it's rated for. Because the PSU is so inefficient, its over-temperature protections would trigger before the unit could even reach its maximum output capability. This sounds quite like what may be occurring for you which would explain why it might seem to work sometimes and other times not so much. I would guess that the times where it successfully runs primecoin+litecoin for a short while it's not quite hot enough to trigger its over-temperature protection. After a few minutes of the load caused by primecoin+litecoin mining it finally heats up enough and trips the over-temp protection shutting the system down. Additionally, your system may be at the limits of your power supply's overcurrent protection which could be the cause of the immediate shutdowns when starting a miner. This is why you have to use the switch on the back of the power supply... to reset the protection circuit. This usually wouldn't be necessary if the problem were elsewhere (i.e. the electrical circuitry of the building, the motherboard, cpu, gpu, etc).

I suspect that there's a triad of things going wrong here that are coming together to cause your problem.

1.) What's the temperature of the room in which this mining rig is housed? Is it air-conditioned? A high ambient temperature may be contributing to this issue. Make sure that the cooling fan of the PSU is spinning up to 100%... sometimes PSUs have defective fan controllers.

2.) Are your 7970 cards overclocked? Are they undervolted at all? What about your CPU? The AMD FX-8350 can draw quite a bit of power and a lot of this power comes from the +12V rail just like for your GPUs. I would guess that you're already over 50A on the +12V rail and coming up on the 60A rating of your PSU, assuming it can even supply that much.

3.) As mentioned before, your PSU -- while adequately rated -- may not actually be providing the output that you need to run your system. If your PSU is performing like the one in the review (http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=188), it's really only giving you about ~600-650W of real output at best which is inadequate for your system (when mining primecoin+litecoin simultaneously). Add to this the fact that a power supply's output tends to degrade with age (how old is yours?) and we really start to run into issues. That said, even if your PSU is/was capable of delivering the power that your system needs, you're still running up against the red line of it's capabilities which is never a good thing.

I don't believe that the issue lies with your CPU, motherboard, or the electrical circuit to which your system is connected. Your power supply seems to be the culprit but this is just my opinion based on the information provided. The other 650W PSU that you tried testing with probably had the same problem as your 750W. It's not necessarily a bad PSU, just inadequate. Without significant undervolting, 650W (~54A or less on the +12V rail) is really pushing it for two 7970s + a monster CPU at 100%.

I always hate to suggest for someone to run out and spend money on new equipment so here's what I'd try for a solution: If possible, undervolt/downclock your 7970s a bit. I run mine at just 902Mhz core and 998Mhz memory at 980mV and still obtain 640Kh/s each. At these clocks and voltages, each card only uses ~170W-180W -- super efficient. If your cards are factory volted at 1.2V core and 1.6V memory like some... they can use almost 280W a piece with a mild overclock. Knowing this, it's easy to see how you can easily exceed the capabilities of some power supplies.

If you manage to get your cards undervolted/clocked and find that the system can then run stable while mining primecoin+litecoin, I'd look into buying a beefier, higher quality PSU. I would suggest a Corsair, XFX or Seasonic 850W unit with a silver or better efficiency rating (they can be pricey, but worth it). You probably won't need to throw away your current PSU, either; just save it for a less demanding non-mining system. :)

Thanks for the excellent advice Xanthe.

1)  We are in winter here - the room is very cool (minus the PC heat).

2)  No cards are not overclocked.

3)  Wow that review says it all.  Seems this PSU is indeed probably the cause.

Question,  it ran fine for just over two months (on GPU mining) before the problem started - is there a possible explanation for that?  Possibly wearing down already?

^^^^^

sorry if not clear, the PSU is just under 3 months old.

Ohh, good to hear it's winter there! From a mining perspective, that is... ;)

Since your cards are not overclocked and assuming the manufacturer set them to run at a sane voltage, I'd think that you would have been ok (but pushing the limits) on a 750W PSU. Nonetheless, it seems that your particular unit may not be quite up to the task. :(


My best guess would be that the extra load from primecoin mining was finally enough to push things over the edge (as I understand it, that was the first time you'd run into shutdown issues?). The PSU somehow managed to support the load of primecoin + litecoin mining for a week, but I suppose that was enough to do it in. Continuously supporting a load that meets or exceeds a PSU's limits for extended periods of time will cause it to wear out exponentially faster than normal (if it doesn't outright kill it). PSU manufacturers often take for granted that most people buying their units (especially the cheaper ones) will use less than half the unit's rated capacity. For this reason they'll often build the units just good enough to say that they're rated at XXX watts, but the unit is not truly capable of delivering that kind of power continuously. Of course, on the other hand, sometimes high quality PSUs are capable of performing beyond their rated capacity, but I wouldn't recommend that! In your case I think the issue is partially the high load that CPU+GPU mining placed on the PSU and partially that the PSU itself may not be the greatest to begin with.

A random thought; another thing that may be compounding the issue is that the overcurrent protection circuit in the PSU can wear out too. Particularly if it gets tripped a lot, it can become weaker and more sensitive causing it to trigger sooner and sooner. I honestly don't know if this is playing a part at all or not -- there are really all sorts of things that could be going wrong to cause the odd issues that you're having.

At three months old, your PSU is still fairly new so maybe you can try exchanging it with the manufacturer. I'd expected you to say it was 5 years old or so. :P Nonetheless, if you still plan to CPU and GPU mine simultaneously, I'd recommend that you upgrade. If you do go this route, definitely find something that's at least 80+ silver rated -- the difference in efficiency will more than make up for the initial added cost within six months of mining.

Anyways, I suppose we still can't be 100% sure that the PSU is the cause yet. I definitely like to be sure before buying new parts. To clarify: when you tested with the 650W PSU, it only shutdown when you tried to run primecoin AND litecoin mining simultaneously, right? I'd guess you were probably just drawing too much from the 650W which caused it to shutdown too. If you have a friendly local computer shop you may be able to get them to bench test your system with a different PSU (say, a strong 850W+ to rule out drawing too much current) for little or no cost. If the problem still persisted then, you'd at least know for sure that the issue is not your power supply. If it wasn't the power supply my next thought would be maybe the motherboard. I would say with near certainty that the issue is not the CPU or memory and probably not the GPUs.

Good luck in getting things worked out! :D

Hi y'all.

Just seeking your thoughts...

I took it (PSU) back in warranty and the shop owner insisted on running tests on it.  With HIS tests it did not fail (but it still fails almost instantly with only the 2 GPU's running litecoin).   He claims it is therefore fine and not faulty.

What are your thoughts on that?

bump

As long as you dont test it with proper (better / bigger) PSU, I would say its the PSU which fails you (Aslong as the shutdown is like you would plug the outlet from the wall, and not bluescreen/stuck/soft shutdown).
Symptoms are quite clear to me, started working fine etc but months under heavy load. Capacitors starts to dry, ICs starts to "wear off" (ripple increases etc...).
Your shop owner (prolly) didnt run it under full stress so ofc in hes point of view it looks ok.