FYI. The thread priority fix went out this week as part of kb3081448. Steinberg is still doing some other testing, but this is the fix for the issue they initially discovered. More on Cubase support when we hear back from them.
Pete.
Happy testing.
Yes, after last windows update all works fine now. Except that some Cubase windows now have ugly white borders. Not all windows, just project and mediabay and so.
Yes, works great again. No white borders here.
Performance is good, no spikes
peakae, thanks for the update 
I might actually give it a go now that this is apparently fixed. I do wish that Steinberg would chime in though.
Regards 