Mining with gpu + cpu - results in low Mhash/sec rate

[pengoau]

G'day

I'm using guiminer and when I set it up with 2 workers, one for gpu one for cpu it results in crap work rate.

With just the gpu worker I am getting about 195Mhash/sec (ATI 5770) adding and additional CPU worker, results in the work rate dropping significantly to liek 25Mhash/sec. Why is this the case?

Thanks

[1713581888]

1713581888

[1713581888]

1713581888

[1713581888]

1713581888

[strictlyfocused]

If your CPU is pegged it cant supply the GPU with anything to process. The CPU is used to feed the GPU. Unless you get your electricity for free CPU mining is a complete and total waste.

If you're set on CPU mining look at the ufasoft CPU miner and set the number of cores to be slightly lower than your actual core count. i.e. 8 core cpu set to mine on 6 cores.

[pengoau]

logic was to try and maximise use of the hardware in the pc to mine so using both cpu and gpu. thanks for the heads up will stick to gpu.

[worldinacoin]

Use GPU mining when you are working on the computer, that should not affect much.  When the computer is free, maybe assign that GPU to one core, run CPU mining on the other cores.  I have been doing that.  For eg for 6 core, I put my 3 GPU in one core, I mine with 4 core, leaving a spare core. 

[racerguy]

Mine on the cpu with idle or lowest priority, this works for me mining ltc's and btc's with my gpu.  Another thing you can do is leave 1 cpu thread free to feed your gpu.