Simple soulution (to all) - make your tests in a defragmentation tool and make the test “with AV resident scanner” as a second one to favor it. The results will show the issue anyway. Or even better do a serie of tests: with - without - with- without.
Just wondering… Not sure if it would work or not… What happens if you put the defrag utility in the exclusion list?
I don’t know but even if it worked it wouldn’t be a solution because COMODO AV resident scanner slows down any disk operation. Nobel price for someone who will work out the rule to exlude >any disk operation< 
also have a feeling that it wouldn’t work anyway. Slowdown is not from scanning defraq utility files. It’s more “low-level” issue IMHO.
If you write music and have a lot of loops and samples, it scans every one of these every time. I have about 34 gigs of samples and loops and moved most of them to a separate drive. Programs like Dimension Pro, Kontakt 3, Drum Core, etc have an immense amount of samples. I started to make a custom scan program to not scan these but got interrupted and never finished but I will now.