A program "PSICOV" "stopped" from a few days on Ubuntu 18.04?
In summary just be patient. psicov doesn't  parrallelise so a tenfold increase in CPU will not hurry it along.

Also psicov is not RAM intensive given the machine you are describing, so you haven't hit a RAM bottleneck. 

I don't know the ps output format you are using I'm use to seeing %CPU and %MEM from ps -aux on Susie and OSX. You should also try,

top -c -u username


or for OSX top -u

You should see the psicov happily chuntering away consuming ~100% of a single process. There is a UNIX/Linux guru specialist on BioSE who could almost certainly provide better diagnostics.