How accurate is the CPU usage display in Renoise?

When I Ioad up iZotope Neutron it only shows around 5 % CPU usage in Renoise. If I look up in Windows task manager it’s almost 40 %. How come that there is such a vast difference?

Vice versa, standard not so CPU hungry VSTs take up around 10% usage in Renoise while they’re only around 3 % in task manager.

Can someone explain this?

The CPU meter in Renoise is only showing the Audio Load. It’s not an overall process CPU load meter. The nearer the CPU audio load gets to 100% the more likely the sound card driver can’t be served in realtime, so crackles or dropouts will happen.