Thank you very much for that gem!
I have been running BlueIris for over a year with 8 x Hikvision ds-2cd2032 (2mp) cameras and 3 (mixed) Dlink ip cameras on a VM server computer sharing an i7 cpu with a total of 3 other virtual machines (all are running). Before changing all of the Hikvision cameras to direct disk recording, BlueIris was reporting 94% CPU usage, now, it idles at 31% and so far, I haven't seen it go over 50%.
Well worth the effort to find that option! Thanks again!