GPUs won't mine at full capacity when all of them are on

[mappum]

I have a brand-new rig with 5x Sapphire 6770's on a Gigabyte 990FXA-UD7 mobo, with a 1200W PSU. It runs Ubuntu 11.10.

A few weeks ago, I started mining but was only getting about 110 mh/s per card, even when OC'd to 960 mhz (they should be twice that much). I thought it was a software issue and tried out many drivers and stream SDK's, and even reinstalled Ubuntu a few times. I also tried various mining software (cgminer, Phoenix, Diablo).

A little later I found that if I only had 1 or 2 cards mining, they would stay at 220 mh/s, but when any more than that and they all significantly decrease. I asked about it on #bitcoin-mining, and was told it is a power issue and was recommended to buy PCIe risers with molex power connectors. I bought three of them and hooked them up, but it made no difference.

It still sounds like a power issue, but does anyone have any ideas what to do to fix it? Thank you for your time, I can pay a bounty if you help me out (once I actually start earning BTC).

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[Oldminer]

Needs more juice.

The power requirements for 4 x 6770's is 1200W but its unlikely your PSU is capable of running that wattage, and especially not under full load 100% of the time.

edit: just reread your post and noticed you have 5 cards so yea no way enough power.

http://forum-en.msi.com/faq/article/power-requirements-for-graphics-cards

[bitlane]

Needs more juice.

The power requirements for 4 x 6770's is 1200W but its unlikely your PSU is capable of running that wattage, and especially not under full load 100% of the time.

edit: just reread your post and noticed you have 5 cards so yea no way enough power.

http://forum-en.msi.com/faq/article/power-requirements-for-graphics-cards

WTF ?

6770's are 120W MAX (on a very bad day) budget cards with 800 Stream Processors....lol  Most are simply re-branded/BIOS'd 5770's
(HD 5770 MAX power draw is approx 110W and I am being generous as 6000 series cards tend to draw more power)
The HD 6790 draws 137W MAX and does so because it's clocked high as shit.....not to mention, a piece of shit (I tried to mine with a couple...lol).

What model of card could you have possibly got that confused with ?

OP, you have more than enough power (and then some). It's gotta be a software issue, settings, device ID problem etc.

[MiningBuddy]

What is your cpu load like while mining with all 5 cards? If it's close to 100% then that could very well be your problem.

[jake262144]

Firstly, you're most probably not even close to 700W. My Sapphire 6770s used to draw 110W each when clocked at 995/300.
Secondly, a power issue will result in stability loss or a shutdown of either the overloaded rails or the whole PSU.

An overheat could very well cause a drop in hash rate but that would likely only affect the overheated cards.

What temperatures are the cards mining at? That's an important piece of information when debugging a multi-gpu rig.
Check the CPU usage, as already suggested.

What operating system, driver version, SDK version and which miner are you using?

[goxed]

Needs more juice.

The power requirements for 4 x 6770's is 1200W but its unlikely your PSU is capable of running that wattage, and especially not under full load 100% of the time.

It's a 6770! rebadged 5770

Running 4x6950 on a 650W PS, Measured VA at the plug = 700VA

[goxed]

I have a brand-new rig with 5x Sapphire 6770's on a Gigabyte 990FXA-UD7 mobo, with a 1200W PSU. It runs Ubuntu 11.10.

A few weeks ago, I started mining but was only getting about 110 mh/s per card, even when OC'd to 960 mhz (they should be twice that much). I thought it was a software issue and tried out many drivers and stream SDK's, and even reinstalled Ubuntu a few times. I also tried various mining software (cgminer, Phoenix, Diablo).

A little later I found that if I only had 1 or 2 cards mining, they would stay at 220 mh/s, but when any more than that and they all significantly decrease. I asked about it on #bitcoin-mining, and was told it is a power issue and was recommended to buy PCIe risers with molex power connectors. I bought three of them and hooked them up, but it made no difference.

It still sounds like a power issue, but does anyone have any ideas what to do to fix it? Thank you for your time, I can pay a bounty if you help me out (once I actually start earning BTC).

Try just 2 cards for a few mins and see if the setup is stable. Then add the third card, and check stability, repeat and rinse. Can you please post the link to your Power supply. A picture of your rig helps too.

Also run the following command in the shell prompt after adding each new card.

sudo aticonfig --adapter=all --initial

[smracer]

You need to use 11.04.

I had the same problem with 11.10.

[BinaryMage]

I run five 5870s on a 1250W, so power is certainly not your problem. 11.10 is very buggy with multiple GPUs, it didn't work on my system either. I would suggest installing 11.04 and Phoenix according to this guide.

[TheHarbinger]

I run five 5870s on a 1250W, so power is certainly not your problem. 11.10 is very buggy with multiple GPUs, it didn't work on my system either. I would suggest installing 11.04 and Phoenix according to this guide.

CheapAssJunk Brand 1200W power supply isn't the same as a top tier brand like a Seasonic 1200W.

[BinaryMage]

I run five 5870s on a 1250W, so power is certainly not your problem. 11.10 is very buggy with multiple GPUs, it didn't work on my system either. I would suggest installing 11.04 and Phoenix according to this guide.

CheapAssJunk Brand 1200W power supply isn't the same as a top tier brand like a Seasonic 1200W.

I'm not sure where you got the impression that the OP was using a off-brand PSU; he/she certainly never said as such. And even if that were the case, any functional 1200W PSU, even if the actual output was less, would be more than sufficient to run a system that likely draws close to 700W.

[mappum]

Sorry for abandoning the thread. I just got around to taking your advice and downgrading to Ubuntu 11.04, and I am now running up at 1200 mh/s. Thank you for the help!

[echris1]

This shouldn't be an issue with Ubuntu 11.10.  I am running 2x6850's at 950Mhz and a 5850 at 860, stock voltages except a slight bump for one card, off of a 650 watt power supply.  Kill-A-Watt says 509 at the wall and its cranking out 845 (250x2 + 345). 

Now to be fair I reinstalled so many times and switched around SDK's and drivers.  I'm pretty sure I am 12.1, using latest cgminer (2.3.1), export GPU_USE_SYNC_OBJECTS=1, diablo kernel (thats the trick to using latest drivers without getting SDK related performance drop). 

Just added the third card yesterday, been running stable all night once I found the sweet spot for the clocks.

So my recommended combo is

Ubuntu 11.10 64-bit, Catalyst 12.1, cgminer, diablo kernel, and P2Pool.

All of this runs off of a Sempron 145 processor, without the CPU bug.

So 11.10 is usable, I never even bothered with 11.04, Always better to move forward =)

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P2Pool, you should be there too =)