rig turns off after ~15minutes

[007158]

4x7950 gigabyte stock clocks(1000/1250)
gigabyte 970a ds3 mb
2x4gb ram
sempron 145
lepa g1000 1000w psu
i have two 1->1  risers and 2 1->16 standard risers
12.8 drivers
2.8 sdk
cgminer 3.1.0

Everyhing worked fine when there were 3 gpu(2x 1->1powered raiser and one in 16x slot), after adding 4th one(2x 1->1 powered,1->16 in 1x slot, 1-> in 16x slot) rig just turns off after about 15 minutes(sometimes more sometimes less), temps are ok i use autofan with target temp 75 and they all run at about 73 all the time while mining bitcoin. I can't turn it on for a while.I used it for a while with lcd plugged in and don't remember it happening(maybe it was to short time). Psu is 4 rail and i tried to split is as equal as i can:
1:mobo+one card(not modular so has to be i guess)
2:one card, impossible to plug anythin else
3:one card+ssd+powered riser
4:one card+powered riser

only way to determine the rails was a photo of pcb in some review so not sure it really is split that way.
Looks like something with psu for me but how can it be to small for this setup?

[lowlevel]

You're drawing too much from the power supply and it's shutting down.  If I recall correctly, gigabyte cards draw 250 watts each at 1000mhz... (might be 225w, can't remember, but either way.. you're up there.)

[007158]

Looked a bit in internet, in every test i found 7950 was below 200w, even if it was 220 it should work well since the psu is solid acordning to reviews and tests.

[MrBilling]

Use a kill a watt. You might be surprised how much power they use.


The 7950's TDW is 200W at stock clocks.

[ThatDGuy]

You're drawing too much from the power supply and it's shutting down.  If I recall correctly, gigabyte cards draw 250 watts each at 1000mhz... (might be 225w, can't remember, but either way.. you're up there.)

From my own experience, this seems accurate.  I would also recommend you take one card out or turn it off before trying to continue.  My experience also included me continuing to try different configurations to get it working and blew out an old PSU.  Luckily the mobo or cards weren't damaged but they certainly could be.

You don't want to be pushing your PSU anywhere near the max - most people will say it's safe to run it at 70-80%.

[lowlevel]

Looked a bit in internet, in every test i found 7950 was below 200w, even if it was 220 it should work well since the psu is solid acordning to reviews and tests.

Well, when I did the same... I found 200 watt for the 800mhz card... so, assuming voltage was the same, 1000mhz is 25% higher than 800mhz, 200x 1.25 = 250watts.

So.. uhm, yeah.. might even be a bit higher

[MrBilling]

I have 2 Sapphire 7950's that are at 1000/1250 and they draw 250-270 W.


I dunno if your using Windows or Linux.  But if your using windows and the computer just turns off with no BSOD and no Windows shut down unexpectedly error thing than its the power supply.

[007158]

thanks guys, guess i'll just run 3 now and get killawat thing to know for sure.

[MrBilling]

Plus you have to add in everything else.


The powered risers will draw 75W each if Im not mistaken.  Plus you got the rest of the system and the SSD.

[zvs]

4x7950 gigabyte stock clocks(1000/1250)
gigabyte 970a ds3 mb
2x4gb ram
sempron 145
lepa g1000 1000w psu
i have two 1->1  risers and 2 1->16 standard risers
12.8 drivers
2.8 sdk
cgminer 3.1.0

Everyhing worked fine when there were 3 gpu(2x 1->1powered raiser and one in 16x slot), after adding 4th one(2x 1->1 powered,1->16 in 1x slot, 1-> in 16x slot) rig just turns off after about 15 minutes(sometimes more sometimes less), temps are ok i use autofan with target temp 75 and they all run at about 73 all the time while mining bitcoin. I can't turn it on for a while.I used it for a while with lcd plugged in and don't remember it happening(maybe it was to short time). Psu is 4 rail and i tried to split is as equal as i can:
1:mobo+one card(not modular so has to be i guess)
2:one card, impossible to plug anythin else
3:one card+ssd+powered riser
4:one card+powered riser

only way to determine the rails was a photo of pcb in some review so not sure it really is split that way.
Looks like something with psu for me but how can it be to small for this setup?

well, if it lasts 15 minutes, then it suggests to me that you could probably get it working with ubuntu on a usb stick, take out one of the RAM sticks, underclock/undervolt the CPU (and RAM)

turn off all the stuff you don't need to use, like the onboard audio and serial ports and what not

[MrBilling]

Maybe I just haven't heard of it but is Lepa a decent brand?


I only see 1 review on Newegg, and 1 review on Amazon of this PSU.  Even though its 80 plus gold rated, running it near 100% capacity especially 24/7 isnt probably going to last long.



http://en.wikipedia.org/wiki/80_Plus

Also look at what 80 plus gold actually means.  At 100% load its only putting out 87% at best.  So 870W.


So even if your cards were only putting out 200W then your still too much power.

[DrG]

Maybe I just haven't heard of it but is Lepa a decent brand?


I only see 1 review on Newegg, and 1 review on Amazon of this PSU.  Even though its 80 plus gold rated, running it near 100% capacity especially 24/7 isnt probably going to last long.



http://en.wikipedia.org/wiki/80_Plus

Also look at what 80 plus gold actually means.  At 100% load its only putting out 87% at best.  So 870W.


So even if your cards were only putting out 200W then your still too much power.

You're failing to understand how PSUs and their power/efficiency ratings work.  Some Gold rated PSUs like Seasonic made ones are well over 90% efficient at full load.

If  PSU is only 87% efficient, it means it will draw 1.0/0.87 * 1000W (in this case) if it was maxed out (assuming it can run the full 1000w - cheap PSUs can't).  87% efficiency doesn't mean it can only put out 87% of maximum power.

Lepa is a decent brand (part of Enermax's budget line).

[ThatDGuy]

thanks guys, guess i'll just run 3 now and get killawat thing to know for sure.

This is the safest route, it might suck to lose 25% of your hashes right now, but that's waaaaay better than losing 100% of your hashes until you have a PSU replacement and/or more equipment!

[zvs]

thanks guys, guess i'll just run 3 now and get killawat thing to know for sure.

This is the safest route, it might suck to lose 25% of your hashes right now, but that's waaaaay better than losing 100% of your hashes until you have a PSU replacement and/or more equipment!

it probably shuts off due to increase in ambient temp

depending on how many peripherals are attached to it and possibly moving it to a cooler location, it probably wouldnt even be stressing it too much.. or just do all that and drop the voltage on a card (* if you can on 7950's dunno)

[007158]

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?

[zvs]

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?

single rail is just easier to manage

and probably easier to sell on ebay too

[GuiltySpark343]

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

[-ck]

...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?

[tom_o]

...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?

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

[007158]

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.