@zapwizard said:
I don't use V-Ray, however once your render starts you should be able to change the affinity of the V-Ray thread in the task manager.
Press CTRL+Shift+ESC to bring up the task manager.
Right click on the task and select "Set Affinity" then de-select some of the CPU cores.
the problem is that vray doesn't use a seperate thread. it seems to run inside the SU thread. so limiting the cores via affinity limits SU cores as well