SOLVED! It is the “Activate Steinberg Power Scheme” that causes this in Cubase 6. I disabled it and all normal.
I have Cubase 6 as well as Cubase instlled. My wife keeps on using her projects with 6, since she is used to how it looks and behaves. I recently upgraded to a Ryzen 5600x and noticed strange behaviour. As soon as I launch Cubase 6, my CPU usage goes to 100%. It is not all from Cubase, Task manager keeps jumping around and shows really strange numbers.
It seems to work normally anyway, BUT buffers cannot be set as low as they can on Cubase 10, so there is something really happening also.
I also tried installing 7.5, since that is the last version that still looks pretty much the same as 6. There it works normally also. My solution could this be to let her use 7.5.
Is there some explanation to this? Could it be that Cubase 6 simply “goes crazy” with the new AMD cores and causes strange readouts?