Topic: rig turns off after ~15minutes (Read 6810 times)

Even a junk 750 watt power supply should be able to handle two 7970's...

have a single core CPU or disable the other cores, undervolt all that stuff (memory, cpu, fsb, etc), ubuntu on a usb, use some energy efficiency lcd monitor with a kvm switch

hmm, do ps2 mice/keyboards have less of a power draw than usb?   does disabling USB slots in bios save you a few watts from motherboard?

i never mine litecoins, but, yeah, gpu's overheating wouldnt surprise me (cough not being able to lower memory to nothing).   sometimes you'll get cards with really crappy thermal paste job that'll have some sensor +20oC  higher than 'main'

Could also be an issue with chipset over heating!!!  can you post your motherboard model?

I had this issue as well and thought it to be bunky PSU at first...(I was in the setup stage for this rig trying out 2x7950 on an 850 watt PSU) I tried at least 30 different configurations with PSU/GPU/Motherboard combo's until I actually took a good look at the board and found that two of my 7950's were sitting right above the motherboard chipset.

Plain and simple there is inefficient heat dissipation for chipset heatsinks on a lot of motherboards, whenever my miner shutdown randomly and unexpectedly, I checked the heat on this (and burned my hand quite a few times!!)

My conclusion on random insta-shutdowns is it typically boils down to 3 things
-Kernal Panic due to driver failures
-Insuffiecient Power Draw from PSU to the motherboard when Cards are running 100%
-Component overheating/damage (chipset or in rare cases CPU)


Hopefully this helps!!!

You must limit your memory underclock to no more than 150 less than the engine speed (driver limitation). Best way to do this with cgminer is to add --gpu-memdiff -150

Mining bitcoin for an hour with 4 gpus at 1100/1250 1020w at most from wall so easily within psu. Powered one more raiser what allowed for more even split between rails. Looks like i'm getting a bit less hashes, stable 570 with 3 gpus, now 550 at most and a lot of time is like 500 or 520. Also cannot underclock memory with cgminer, setting gpu works ok but memory always stays at 1250.

For anyone who wants to do this i'd definately recommend single rail psu.


edit: weird gpu-z shows 1250memclock and afterburner shows 500(what i typed in --gpu-memclock) when i open it while mining.

edit: so it failed anyway, only after 3 hours not 15 minutes, while pulling 1060 from wall, 4 rail psu sucks, especially that 2 rails are not modular(atx+2xgpu,2gpu!!!), will just get 1300w single rail psu.

See my thread https://bitcointalksearch.org/topic/is-my-kill-a-watt-wrong-says-pulling-almost-1300w-from-1200-w-psu-205406.



I am was having power draw questions too.  I think that mining LTC on top of OC ing the cards makes you draw alot of power.

Same thing happened to me.  2x "Gigabite" 7970 with 750 Watts OCZ power supply.

Shut down after both cards came online to mine with GUI miner.  Upgraded to a 950 Watt PSU, problem solved.

Flashed to f43, looks a lot better now. Had some problem with no video on booting, only could run 2 cards at once and not in any combination... but did this finally. Clocks are 1000/1250 tho not 900/1250 but voltage is 1.09, autofan works fine at about 500rpm less to keep target, hash is more or less the same - 600 on litecoin. Most important thing, it takes 800w from wall so significant drop. Maybe i can get the 4th gpu going, pretty sure it'll be fine for bitcoin

edit: power draw for bitcoin at 1100/750 770w about 560mh/s fluctuates a lot unlike previous bios where it was very steady in cgminer, also there is difference between cards and before there wasn't bu i guess it's a lot bettter now


edit 2: Could some moderator please move it to mining support, i wated to start it there but something went wrong.

I got the 4th card in but cgminer starts with it being at 500/100 even when i specified engine and memclock for each card seperately, when i disconnected on of proprly working cards this one starts to work fine(1100/750). Can it be that it lacks power and acts this way(before it just turned off so dunno)? Its connected to a rail with mb(2x pci-e not powered, proc, ram and other stuff), non modular so can't really change much besides powering 2 more risers. Also i can't change engine and memclock in cgminer it's fixed ant this 500/100 or 500/150 for litecoin.

Still won't be able to use 4 gpus and i have 4, i'll try to return the psu and just get a bigger one and then figure out max performance.

Yep, you're just out of power. Mine the real coin at lower power and be happy.

Mining litecoin with 3 gpus pulls about 1k from wall(bitcoin is about 900w), something must be wrong?
Beside gpus i have cpu, ram, ssd, usb wireless.
Solid psu if it wokred for 10 minutes with one more gpu i guess

Would prefer not to flash bios due to warranty.

flash your cards to F43 bios
It will lower voltage to 1.09... and save you around 40W per card.
Here is the tutorial:
https://bitcointalksearch.org/topic/gigabyte-wf3-7950-10001250-125v-stock-197200

Or underclock the CPU, that's what I did. If it isn't your main pc you could even disable one of the cores reducing draw even more!

Most likely a power issue as mentioned.  If you put a Kill-a-watt on it and start mining you'll notice the power draws goes up until the temps reach a steady state.  Probably when the rig shuts off it is overextending itself.  Either take a card out, undervolt or downclock one card to reduce the load.  Maybe downclock the hottest card.

bitcoin mining over intensity 9 is wrong

it went all night on stock clocks mining bitcoin, i switched to litecoin now and it turned off after getting few shares. Litecoin intensity is 19 and bitcoin 16(any higher and cgminer shows some very high hashrates but doesn't mine anything and gpu usage is like 37% some other random amount).

no power saving

i tried with some old 400w nonapme psu(connected one 8pin to one card and one 6 pin to other) everything freezes on start of cgminer.

This is what sent me mad for a day and nearly resulted in an RMA of the GPU! Check it!

...you wouldn't happen to have some power saving feature enabled that automatically powers down your computer when it's not in use would you?

You could buy a second PSU (even a 500w one), and use the second PSU to run the 4th card. You will need to "jump" the PSU to turn it on:

http://forum.overclock3d.net/showthread.php?t=394

single rail is just easier to manage

and probably easier to sell on ebay too

temp is not an issue i think, i put it outside of my open setup so it sucks completely fresh air from 30cm fan. Looks like lack of power. If i were to buy a replacement should i go for single rail or it doesn't matter?