I've been wondering if it's still profitable to do CPU mining? I have tried Minergate with limited success and recently tried mining monero with XMR-Stak. Mainly just thought I'd stop lurking and say hello!
It depends.
If you have a cpu with lots of cache like the ryzen 1700/1800 or Threadripper 1920x/1950x you can still make a profit. But its not much.
As for the cpu in the typical mining rigs g3930/4400 its not even worth the effort at this point.
I have found out that Ryzen CPUs do well on Argon2d and 2i algorithms but i7 are much better at mining Yescrypt coins.