I am also getting a general OS slow down when the miner kicks in;
I ran htop to check out usage. And something is chewing almost 100% of one of the cores and this is also when the system is laggy and slow and I believe is contributing the OS freezing.

Any ideas what process this is ?

EDIT: sometimes it’s on core 3, others it’s core 4 changes every reboot

http://i184.photobucket.com/albums/x223/rayd89/FB045C2A-A398-4D45-A5C2-388D7CE3334F_zpsyyzvaob3.jpg