Recently I am playing with OpenVMS with SIMH. The document at Running VAX/VMS Under Linux Using SIMH greatly helps me for the installation and setup.
A few things changed since the document written.
First the latest code for SIMH could be retrieve from SIMH at GitHub. It helps me to compile on Slackware64 without problem.
Second, adding “set cpu idle” in the vax.ini file will greatly reduce the CPU usage.