I have started cpu mining XMR on my 6x rigs while the GPUs mine ZEC.
Can you say the components and the hash rate?
H81 pro btc R2.0 mobo
G1840 cpu
6x zotac 1070 mini
8gb corsair ram
EVGA GQ-1000 psu
16gb USB key
https://www.amazon.com/Lexar-JumpDrive-16GB-Flash-Drive/dp/B00S5V5PMY29.1 H/s 6 hour average XMR @ nanopool ( at current rates with 10c kwh electric the cpu will generate $16 profit a year, and roi on its own in ~3 years ) Note cpu mining hashrate is all over the place (less frequent shares); so it takes a while to get a good idea of a cpu's average hashrate.
2655.4 Sol/s 6 hour average ZEC @ nanopool ( all 6x cards cc200, mc400, powerlimit 125 on nvOC )
using 880 watts at the wall
Currently only running +cpu on a few of my rigs, but all have been stable for over 24 hours; so I will deploy +cpu mining on all my rigs tonight / tomorrow. I have an i3 on the way to test as well.
If all my rigs are stable with +cpu mining I will add it as an option to the next version of nvOC. Also looking for alternative cpu mined coins to try; if anyone has any recommendations.