Right then…
So Looking back at various threads
I’ve been chasing this since at least Nov last year… so 8 months!!!
In that time I’ve had a few helpful suggestions but no one has been able to tell my why cubase is freezing with WDAUDIO crashes, just that I should use windows RT.
For 8 months I’ve been trying windows RT and could NOT get it to work. Again no one, and more importantly no one from Steinberg has had any ideas as to why or how to help.
So again in frustration about this I reached out to Pete Brown at Microsoft @Psychlist1972 and my friend Vin (TAFKAT) who is the dev of DAW bench and a system builder in Australia.
Within a few hours I had the answer.
it was infact the MMCSS issue that was causing this. After i downloaded the ‘tool’ and extended the threads to maximum everything ran perfectly and windows RT has been running fine for all my devices.
So, on one hand I’m glad it’s fixed but…
why did NO one from Steinberg know about this and help me in 8 months? Is this becasue they all are Mac users now, and they don’t know about this issue on windows/Cubase? After watching Dom Sigales recently bashing Windows it does seem like Cubase is becoming more Mac centric 
Cubase is the only DAW I have that has this MMCSS limitation that’s why I saw no issues with Studio One or Reaper with the same hardware.
Why is the MMCSS thread limit neutered in Cubase if it can cause this?
@Martin.Jirsak I’ve a feeling this has been going on for quite some time, so I’m genuinley surprised it’s taken me contacting Microsoft to get a solution.
So for anyone else who has a problem like this it’s a simple fix, see @Psychlist1972 post above with the download link for the little application that will remove the thread limit.
M