The defrag comment was a joke ( hence the Razz Emoticon with the tongue sticking its tongue out → 
<–)
I don’t have Cubase 6 yet to test, otherwise I would report as much as I could and what I see happening.
A lot of things can be seen via window’s resource meters… I don’t know how far you want to look into what is happening. I like to find the root cause if I can. I kinda wish I ordered it to see what the system is doing when variaudio is sluggish but I convinced myself to wait for a period of time as I did the last few upgrades to save the last of the color in my hair from troubleshooting and investigating.