Hi,
I'm trying to mine Darkcoin on GPUs and Quazarcoin on CPU - please help

I have
CPU i7-4470k
and two GPU cards nVidia 750 Ti
When I run the ccminer50 I get around 3.1MH for GPU both cards, for Darkcoin at pool,
then when I run minerd for Quazarcoin, which is CPU only, it runs ok, but
the mining of ccminer50 (Darkcoin, GPUs) drop down to very low numbers

Is it because ccminer still uses CPU? On performance monitor the CPU usage is not bigger than 15% - ?
Also, I tried to run minerd (Quazar, CPU only) with only 2 logical threads, it does not help at all.
How can I mine same time on CPU and GPUs?