100% CPU bug Windows finally solved (Multi GPU) with catalyst 11.12

[disclaimer201]

Didn't notice any performance loss while the cpu bug went away completely. All lower end cards though.

[jwzguy]

I can answer my own question now. The video card driver gives a minimal improvement over 11.6: at lower aggression settings, phoenix gets about 1 mhash more, but about the same at max settings.

The OpenCL version 2.6 included in the 11.12 package will completely hose your system for a 10%+ loss, you'll then need to uninstall the OpenCL installation or use the "uninstall all ATI software" option, and also find and delete C:\Windows\System32\amdocl64.dll, C:\Windows\System32\amdoclcl64.dll, C:\Windows\System32\OpenCL.dll, and reinstall the old OpenCL to get your performance back.

I can't test multi-GPU CPU usage though, so try to install the new driver only (through device manager, for each video card, after extracting the driver components, on Windows) and rebooting.

All I had to do was copy the 6 dlls mentioned in the other thread from 2.5 on top of the 2.6 ones. That fixed the performance drop and CPU usage went back to 100%. A lot less hassle.

[pooler]

What about Linux ?

I can confirm ATI drivers version 11.12 solve the problem under Linux, too. The CPU usage of phoenix went down to 1%.
Now I can mine both Bitcoin and Litecoin in the same rig... Yippee!

[Mousepotato]

All I had to do was copy the 6 dlls mentioned in the other thread from 2.5 on top of the 2.6 ones. That fixed the performance drop and CPU usage went back to 100%. A lot less hassle.

Link to other thread plz?

[tiberiandusk]

CPU usage for me went from 100% to around 60% or 70%. It bounces around. On my single card machine my reported hashrate went down 20mhs but my pool is saying it is the same as before based on submitted shares.

[Sannyasi]

i've posted this in a couple other threads- i run a 5870 and 5770 with a slight loss in hashing power usin GUIminer but the CPU bug is gone for me

[Tullphan]

Another satisfied customer. Bug is gone with marginal performance loss.

[jwzguy]

All I had to do was copy the 6 dlls mentioned in the other thread from 2.5 on top of the 2.6 ones. That fixed the performance drop and CPU usage went back to 100%. A lot less hassle.

Link to other thread plz?

Scroll to post 11.
https://bitcointalk.org/index.php?topic=54693.0

[rotrott]

CPU problem solved for me.  I'm running debian.

[Grinder]

I can hardly believe it, it actually works! 2x 6950, GUIMiner, W7 64bit. 1-2% CPU usage, no noticable loss in performance.

[disclaimer201]

I can hardly believe it, it actually works! 2x 6950, GUIMiner, W7 64bit. 1-2% CPU usage, no noticable loss in performance.

Could any of you please tell me if you got it to work on a mainboard with an integrated gpu? I got rid of the cpu bug only on my non-onboard gpu rigs. I do use the internal graphics to run windows, in order to not lower the hash rate while working. Cheers!

[Inaba]

Still seem to have the problem on one Win7x64 machine, but not on another.  WTH

[grue]

Still seem to have the problem on one Win7x64 machine, but not on another.  WTH

downgrade to 2.1. no cpu bug, no performance loss either

[disclaimer201]

Still seem to have the problem on one Win7x64 machine, but not on another.  WTH

downgrade to 2.1. no cpu bug, no performance loss either

I believe there were performance improvements with the newer sdks, so downgrading to 2.1 would mean quite a loss in performance, or wouldn't it?

[Inaba]

No, I've not heard of any performance improvements. 

But downgrading isn't a option, as the one having the problem is is my primary gaming rig.

[portron]

Upgraded to 11.12 on one of my rigs... 2x6950 went from 740mhash to 680mhash...  but the CPU bug is gone.  Not sure if the tradeoff is worth it on this box.

[Inaba]

Well, even though I upgraded my gaming rig, it seems the driver update didn't take.  I re-did it and the CPU bug does indeed seem to be gone on 11.12.  Hoo-ray!