undervolting r9 280x linux - possible?

[Evil-Knievel]

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[1714858235]

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[1714858235]

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[frank754]

I've got two XFX R9 280X Radeon cards, each in a separate computer, both running Ubuntu 13.10. I just built the second box yesterday. After much tweaking, I can get the first one to stay at 724 KHz when I'm not doing anything else on the computer.
I've had this box going 24/7 for almost 3 weeks now at 724 (when all else idle), plus the temp stays around 72 C.
I use this config:
-I 13 -g 2 -w 256 --gpu-engine 1027 --gpu-memclock 1500 --gpu-powertune -5 --no-submit-stale  --auto-fan --thread-concurrency 11200 --lookup-gap 2

I found that changing the engine or memclock higher actually makes it go slower, and powertune of -20 or -5 don't make a difference.
TC of 8192 which a lot of people use, also makes it go slower. I delete the .bin files before use (Tahiti)
So I'm satisfied with it, for sure.

On the second box though, with the same card (and exact same command line), it will start out at 700+ after the first 30 secs or so of "settling in", but after a few minutes gradually drop down to an average of only about 609 KHs over a period of time, with nothing else running and unattended. Also it runs around 76 C at this lower rate.  Wonder what's the reason for this?
Also want to mention, I'm using a USB stick wifi unit for internet, while the first box is direct to the Ethernet via cable. May that or the pool itself have some influence on what gets accepted and how fast?

[Gazza1]

How are you guys getting your Linux boxes to read cgminer gpu configs?  My Xubuntu 13.10 with cgminer 3.7.2 doesn't read the --gpu-engine or --gpu-memclock settings.  Either in the bash script or the config file.

VBE7 has been a life saver since I just put all my settings in there.  But I did notice the linux thing today when I was fooling around.

@Frank, my 280x's love tc 11200 the best, with 1050/1500, but others have success with 1020-1100 in ratios of 10.  /1500

[fran2k]

ATIFLASH or ATIWINFLASH will work for flashing the BIOS.

Thanks for the pointer. Now comes the question: What to flash?
Is there any tool which is capable of adjusting the R9 290X bios?

Start here, litecointalk mining section, specially The Stilt threads. Like this thread which is for 79xx & 280s GPUs. Lot of optimized BIOS there.s.

Is there some work being done on 290x, I guess we will have some clear options in a few months, nothing clear by now for me. 290s are little bitchez, I prefer a lot 280s.

[vm_mpn]

Here is another link... Not sure how helpful it's for your situation: http://www.cryptobadger.com/2013/10/undervolting-in-linux-via-modified-bios/

Vadim

[ilpirata79]

Hi there
Is there any way to undervolt r9 280x under linux (SMOS/BAMT to be exact)? I've seen people changing BIOS for HD7970 to undervolt but didn't found any bios editor for r9 280x.
Anyway would rather like use software command if possible. Or I have to use Windows for that purpose?

Cgminer of course ignores voltage settings.

not the prettiest or simplest while looking for that stable voltage, but this looks to be a verified way to undervolt in linux.

http://www.cryptobadger.com/2013/10/undervolting-in-linux-via-modified-bios/
not sure if it is working 280xs though... also what kind of card do you have. it simply may not be voltage unlocked in the first place.

Confirmed that VBE7 does work with 280x cards. Flashed half a dozen Gigabyte 280xs this week, and they're all hashing @ 725KH/s @ 1.019V. Dropped consumption for a 5 GPU rig frim 1450W to 1250W, and lower temps as well. Test on one going lower and lower, and then flashing the others only took me ~5-10 minutes per card.

What are the other settings that you're using? I mean core and mem in cgminer/sgminer.

Did you also change those settings in the bios?

Best regards,
ilpirata79

[johncarpe64]

Hi there
Is there any way to undervolt r9 280x under linux (SMOS/BAMT to be exact)? I've seen people changing BIOS for HD7970 to undervolt but didn't found any bios editor for r9 280x.
Anyway would rather like use software command if possible. Or I have to use Windows for that purpose?

Cgminer of course ignores voltage settings.

Use 7970 editor, they are the same.