ImgBurn device buffer fluctuates

I’ve noticesd the last few times i’ve used ImgBurn that the device buffer jumps from 100% to 10% and back up again, and hovers around 2X burn speed. I though my HDD must have needed a defrag, as it was pretty full, but after that didnt help i did some searching. I found that if you have 2 Primary and 2 secondary interface devices in device manager. Remove all of them, and reboot so it re-installs them. Fixed the problem for me, burning back up to 12X again.