Crashing Rig...why...!?


I've build a basic rig with the following components:
ASRock BTC motherboard
Intel Celeron Dual Core 280 GHz
6 X Sapphire Nitro RX480 4GB

It runs fine with 5 cards but when I add a 6th it runs for awhile then crashes.

I'm running everything as it came out of the box, do I need to modify any settings? Are there any components that aren't up to the job?

Probably the PSU is to blame for that. I'm not sure what exact power figures we're talking about on RX 480 but it could very well be 6 x 150w = 900w plus CPU and the rest, more than PSU maximum capacity.

Try 5x cards and check the power at the wall with a kill-a-watt or similar device. Try lowering the clocks with MSI afterburner and check how the power consumption decreases. And add the last GPU when you are sure you won't exceed the power rating.

Sounds like a plan. Should have bought a more expensive PSU, buy cheap buy twice.


Rigs like yours are reported to be drawing around 800 watts after tweaking. So 1000 should be enough, but you have to do the tweaking. Check anorak's thread for modded bios, search other threads here for clock and mem settings and undervolt settings.

i used to have the same prob even using 2X750 W psu and an ASROCK H81 PRO BTC
try to change the GPU i mean keep only 5 GPU but change one of them then look if it crashes again
if no you better change the GPU from the supplier

Do you use Claymore ? Checking the log file could be helpful.

It could be :
- PSU, never had a problem with EVGA, 1000W should be enough but it may indeed be too little for 6 cards
- a faulty card (characterized by a recurrent "GPU X Hangs in OpenCL call" message just before the crash in the log file
- ground loops, especially if the rig didn't reboot normally after the crash
- driver version (try with the latest)
- claymore version (i experienced some crashes with claymore 9.1 and 9.2, try to downgrade in 8.0)

If your rig is headless (without screen), try to plug a screen on it to see if it's better.

Good luck !

That rings a bell...thanks guys.

solved your problem ?

Too soon to tell. I don't get as much time with my baby as I'd like. I'm going to try out some of the suggestions above tonight if I get time. It does look suspiciously like a dodgy card, I'll swap it for one that I know is working and see what happens.

Been running for an hour with Claymore v8 with no problems. Although I'm getting the same H/s with 6 cards as I did with 5 cards using Claymore v9.3...!! Ah well, the joys of mining.

Just a short follow up. Using the Trixx utility I reduced the Watts by 25% for each of my 6 GPU's. I've run them all for 24hrs using Claymore v9 with no problem. Getting an average of 1.2 kH/s.

Undervolt and underclock all your cards....
More sol/s per watt :slight_smile:

I'm going to try this next. What do they say about pride and falling? The rig fell over again last night, running again with a further reduction in Watts.