Topic: Can't get six or five 7950s working. Was working before. [RESOLVED] (Read 2313 times)

I'm not familiar with the ASRock 970EX4 enough to say that it can run five GPUs. Check this out for motherboards that may work.

cryptokeeper...I was wondering if the ASRock 970EX4 and Intel Celeron G1610 Ivy Bridge Processor, would be able to run 5 GPU's on windows 8?

I was using your 6GPU setup from your site, but after reading your post and seeing as your only using 5 GPU's I figure I should opt to buy the cheaper mother board and just run 5 as well. Thanks

I tested each GPU individually and with others. Yes 1600W for five works. Six is pushing it. Read this post to get six working in Windows 8. MSI Twin Frozr 3 don't need to flash BOIS because it's voltage is unlocked.

When you tested each GPU, did you test them individually or with the others plugged in. Or one by one. I'll give that a try both ways in just a moment. So should I just count on only using x5 with a 1600w? If so thats fine for now.

Any ideas how I could find the 12.6 trick for windows 8? I had windows 8 with 13.1 earlier and device manger saw all 5 of them that were plugged in at the time just fine. However, when cgminer started I would see all the hash rates jump up where there suppose to be, but then the screen would either freeze or go blank and I would loose all control, it was like the driver was crashing.

Not having to short any pcie slots would be nice, I had to short one of the 1x on my gigabyte board. It has no problem though seeing all 6 in ubuntu or xubuntu, I just cant run cgminer with a thread concurrency above 1792 or all the cards but one report as off, on the flip side if i run at 1792 they all hash at 150 or so, but i get 10 HW error a second a card so thats issue as well.

I'd prefer to stick with windows 7/8 so that I can utilze afterburner to turn down the voltage, though I suppose a bios flash is always an option?

I figured out it was the rail from testing each GPU with it's closest rail. Then I found the GPU that didn't function in cgminer. So I tried it with a different rail and it started working. Hence I moved the power cable to another rail and got all five working. I could probably do six again by swapping out PSUs but the power consumption was going past the 1600W rating when I had six going. I had to underclock and turn intensity down to get it stable. If I were to do six again, I would use two 1000W PSUs.

To get six GPUs working, I used 13.1 on Windows 8 a 12.6 trick. I can't find the link at the moment but it's somewhere on this forum about six GPUs to work on a motherboard. Also no shorting PCIe slots on the MSI Z77 GD65.

I have the same PSU and Graphics cards as you and am struggling to get all six working. How did you figure out that one of your rails was malfunctioning? Also, did windows 8 see all six right off the bat? Just installed 13.1 and they worked?

I'm using an A4 FM2 processor with a gigabyte F2A85x-UP4 but so far its been nothing but a pain in the ass lol. If you have 6 msi r7950 twin frozr working good in windows 8 with that msi board, I might be making a return to amazon soon lol

I figured it out. One of the rails on my PSU is malfunctioning. I moved the GPU power cable to a another one and it works now.

I find that the hotter my cards are running, the more power they draw and the less stable the system is. How's your cooling? 85C seems pretty hot. I like to keep my cards around 75 for optimum performance/card longevity.

If you just put these two problematic GPUs into the mining rig, does they work?

I think the mother board could be the source of problem.

Can you try lowering the mother board memory frequency? Lower the CPU frequency? Or change the hard driver?

I had six cards working on the mining rig before. It was working fine. I tried 13.1, 13.3, and 13.4. All crashed.

I suspected it might be the motherboard as well but it can start the other GPUs just fine. So that's when I suspected it was the two GPUs until I put them in my office computer.

If you just put the two GPU (which is in office computer) into the mining rig, does it work? If it works, then add more GPU on the mining rig. I suspect something might be wrong with the mother board.

Can you try Catalyst 13.4?

Does it happen more on LTC?

The office computer does not crash at all. It is solid. I was using all powered risers. I don't think it's a power issue. I am able to stay below the killawatt meter.

Does the office computer crash every morning? Maybe your computer is doing something else and used more power.

Try powered riser on your mining rig (with 6 GPU).

MSI Z77 GD65
MSI 7950 TF3
8GB RAM
Lepa 1600W PSU
Windows 8
Catalyst 13.1
All powered extender cables

I had six cards MSI 7950 TW3 working just fine. After the third day, it kept freezing, resetting or shutting down. Killawatt said I was going a little over 1600 watts. I thought it was consuming too much juice. So I turned down the cgminer tweaks and got it below the wattage of the PSU. This time it kept freezing so I reinstalled drivers. Still had same problems so I reinstalled Windows 8. I just pulled the card that got sick or dead and put it on my office computer. Then I had five cards working. It kept on freezing. Pulled another sick or dead and put it on my office computer. Now I have four working together on the miner and two in the office. Each time I get a sick or dead card, I tune down the cgminer settings. The four GPUs on the miner are now getting 620MH/s or 620kh/s in Litecoin as well as the two in the office without crashing. Thought it might be heat problems but the two in the office got up to 85 without a hiccup.

So two of the cards do not cooperate with the others. I don't know why. The two GPUs in my office computer run cgminer like a champ. I thought it might be the motherboard of the mining rig so I tried different slots and different extender cables and swapped different GPUs around with all the GPUs. The motherboard works fine with other GPUs and cable extenders. Just not the two.

TLDR: two of my GPUs can run cgminer in the office computer perfectly but crashes on the miner rig. The miner rig motherboard and extender cables work fine with four GPUs but not the two that is now in the office.

What do you think?

Thank you.