Reallymine - processes and resources

[Gregoras]

Not really issue, rather question.
I'm running reallymine on local Qnap server in VM for 1 TB drive. It works, but is really slow. I suspect, that 2 cores and 4 GB RAM is not enaugh. What resources you recommend for running reallymine? Is more important to have more memory or better CPU power?
And how many processes should starting reallymine decrypt under linux? In my case I see 5 processes in log, so I'm not sure if I, by mistake, not running multiple instances of application for the same drive.