Bitcoin Forum

I just started mining last week.

I added a 2nd 5830 to my rig.

Before CPU usage was 1% on my Core i7 930.

With the 2nd GPU, my CPU is @ 14% usage when mining and when the 2nd instance of Phoenix 1.4 is open.

What should I do to get CPU usage down?

I'm on Win7 64bit.

Thanks!

You can't.

It's the nature of multi-GPU mining - it'll max out at least one core.  No fix for it yet.

Agreed, it's the nature of the beast.
Dual 5850's do the same here on i7 regardless of cpu speed.

What about a 3rd or 4th GPU.  Will it go up another 14% and another 14% again???

How about if I had 3 GPU's on a Singl core Sempron 140, what would my CPU load be like?

it just makes the cpu 100%, or as your Core i7 has 8 threads, it will max out one thread per GPU instance when using multiple GPU

I have a dual core Athlon II 3.1Ghz with 4 GPU. The CPU is at 100%, all GPU still run max Mh/s :)

Consider yourself lucky as I get 50% cpu usage with both my 6950 and 5850 mining. The best I can get is 25% usage by limiting the affinity to only 1 core for both miners.

I've heard linux doesn't have this problem though so you could try that.

Can't do linux for my main system, but maybe for future builds.

Also for a dedicated system, I suppose you could disable some cores and underclock it to save on power?  Or do you think this would hurt the GPU performance?

Strange its now using 27%  ???

I'm 100% sure I had both GPU's running and was only using 14% earlier today.

I did start and stop phoenix several times, but still thats strange.

Any clues?

Anyone have any ideas?  I hate that it was working with 2 GPU's mining with 14% CPU load now its like 26% :(

i have started a thread at amd dev forum - opencl section about the 100% cpu usage bug with >1 gpu installed. feel free to jump over there and post your support for this issue being addressed...

http://forums.amd.com/devforum/messageview.cfm?catid=390&threadid=153211&enterthread=y