Best SDK for 7970's? Seeking 99-100% GPU usage!

[NLA]

Currently testing my 7970's in Windows before I flash the BIOS to the settings I want (voltage, clocks, for maximum performance) and switch over to mining in Ubuntu, and I'm testing with AMD's 2.7 APP SDK. When I'm mining with just one or two cards, I hit 99% GPU usage and I get all the performance out my 7970's; when I'm mining with five cards, GPU usage wildly fluctuates between 70-86% and I net substantially lower hashrates. What gives? Less GPU utilization equates to lower hash rates! I'm suspecting that either the SDK or mining in Windows itself is to blame.

Specs:
5x 7970's: 2 Diamonds, 3 Sapphires
Windows 7 Ultimate x64
AMD 11.12 Drivers + AMD APP SDK 2.7
cgminer: process priority high, CPU usage between 6-15%, poclbm kernel, 2 threads, intensity 10, powertune 20, mining with EclipseMC

• Any suggestions?
• Any evidence to the contrary that SDK 2.7 works just fine? Is it just me having the issue?
• Do the Linux and Windows SDK's have the same performance, ie. if SDK 2.7 is netting 70-86% GPU usage in Windows, it will be the same in Linux?
• What is the best SDK to use with 7970's in Linux? In Windows?

[NLA]

WELL, oddly enough, it turns out the new cgminer (2.4.3) has higher intensity limits than the version I was using (2.4.1), up to 14 from 10. My GPU usage is now between 91-95%.. which is better, but still not the 99% I'm aiming for.

[-ck]

SDK 2.6 is the best for 7970s. Intensities up to 14 have been allowed for a long time in cgminer, it's not new. Intensities above 9 on windows will give you the 100% cpu bug. If you can't get 100% usage then you may be having issues with the crap driver versions, not the sdk at all. Drivers 12.3 and 12.4 have uniquely different bugs if I recall correctly on windows that prevent either extra devices working or make extra devices fall into low power mode, but can't speak for the newer driver versions. Pretty much the oldest amd driver that supports the 7970 is the best driver (for mining) and it has only gotten worse with every next release.

[NLA]

Odd, I swear when I was using cgminer 2.4.1 it said the intensity limit was 10.

Right now I'm using the 11.12 drivers, which I believe are the oldest drivers with 7970 support, so I'm not sure what to say. One GPU going, perfectly fine. Many GPU's running, GPU usage is between 90-95%, so I'm missing out on a good bit of performance between all the GPU's.

[-ck]

Odd, I swear when I was using cgminer 2.4.1 it said the intensity limit was 10.

Right now I'm using the 11.12 drivers, which I believe are the oldest drivers with 7970 support, so I'm not sure what to say. One GPU going, perfectly fine. Many GPU's running, GPU usage is between 90-95%, so I'm missing out on a good bit of performance between all the GPU's.

Ignoring the gpu usage reported, what hashrates are you getting? Max you should get about .6MH per Mhz of engine clock speed.

[Prattler]

Currently testing my 7970's in Windows before I flash the BIOS to the settings I want (voltage, clocks, for maximum performance)

How does one edit the BIOS of 7970? RBE doesn't support it

[NLA]

Ignoring the gpu usage reported, what hashrates are you getting? Max you should get about .6MH per Mhz of engine clock speed.

Well, it's hard to ignore the reported GPU usage, since I've been noticing that low GPU usage corresponds to low hashrate, and high GPU usage corresponds to high hashrate. So while the cards might be capable of hitting 550MH/s at stock settings, when I run all the GPU's in tandem I might only be hitting 450-480MH/s per GPU. I'm noticing about .5MH/s per MHz.

Also, I just used ATIman to do a clean uninstall and re-install of 11.12 and the 2.6 SDK, and cgminer is crashing when I choose a single GPU or all GPU's for mining. Do I need to compile for Windows from the latest commit?

And by the way, ckolivas, do you have any recommendations for Linux (Ubuntu) drivers + SDK for a rig with 7x 7970's? I've been reading around that some people like 12.2 + 2.6 for 2x 7970's, but is it different somehow with 7x 7970's? I forget if AMD's Linux drivers have a GPU limitation like they do in Windows.

How does one edit the BIOS of 7970? RBE doesn't support it

The old fashioned way, with a hex editor. RBE should be able to support 7970 bios editing, but the dev seems to believe that there are new security mechanisms to prevent BIOS editing.. which there aren't.

This post over on the OCN forums outlines how to edit the 7970 bios to change clocks and voltages:
http://www.overclock.net/t/1196856/official-amd-radeon-hd-7950-7970-owners-thread/4220#post_16496161

[Prattler]

Thank you very much!

[NLA]

Thank you very much!

Donations appreciated!

Just did a clean uninstall/re-install with ATIman and installed 11.12 + the 2.5 SDK, the hash rate is terrible even though I'm getting 99-100% GPU usage (~482MH/s on stock settings with SDK 2.5, whereas SDK 2.7 did 550+MH/s). Also, "cgminer -n" identified my 7970's as "Lions" and not "Tahiti", so I'm guessing 2.6 and 2.7 are the only SDK's that will work properly with the 7970.. trying again with 2.6 before I return to 2.7..

EDIT: Just finished the clean 11.12 + SDK 2.6 install, and oddly enough it seems to not be crashing. Sometimes I can only run one GPU for mining because running all GPU's ends up with a cgminer crash. Currently have very reasonable CPU usage from cgminer (5-12%). GPU usage is still all over the place when mining with multiple GPU's.. some GPU's are hitting 93-99%, some are in the 80's.. its just a mess. Intensity at 14.

[-ck]

You're on windows. Do not put intensity above 9 as I have already said. There is a chance you're actually running out of CPU when you enable extra devices. When you change drivers and SDK with cgminer, make sure to delete any .bin files that were generated previously. Pretty much the same combination of drivers and sdk on linux are suitable as on windows. I use the 11.12 drivers that have the 7970 hotfix to get the 7970s working. You cannot run 7970s with SDK 2.5; if it's working with that combination it's only because cgminer has cached the .bin files.

[Bigal]

I had a similar problem in widows 7 after adding a fifth gpu, 4 gpus ran great, 5 sent cgminer into a tail spin with the hash rates, but worked fine under ubuntu, I figured out it though I had to set the gpu threads to 1 then got full steady hash rates on all 5 gpus

[-ck]

I could not get the 4th to work until I increased the PCIE latency in the bios from 64 to 96.

[NLA]

You cannot run 7970s with SDK 2.5; if it's working with that combination it's only because cgminer has cached the .bin files.

Odd.. I wonder where "Lions" came from, then?

I had a similar problem in widows 7 after adding a fifth gpu, 4 gpus ran great, 5 sent cgminer into a tail spin with the hash rates, but worked fine under ubuntu, I figured out it though I had to set the gpu threads to 1 then got full steady hash rates on all 5 gpus

Reducing the number of GPU thread doesn't reduced hash rate?

I could not get the 4th to work until I increased the PCIE latency in the bios from 64 to 96.

Sadly my BIOs has no options to change PCI latency.