Cubase 10.5.20 Maintenance Update

No thanks here…Just installed it and immediatly got CPU overload while playing a heavy mixproject which played just fine yesterday.
Around 85-90% CPU load, but now in the red so dropouts.
Two (FW and USB) interfaces, both same results.
Now I can’t play this mix anymore.
What happened?
nothing changed on my computer or settings since yesterday, only todays update of Cubase.
Tried the “suspend vst3”, because that was the only difference I read, but no advantage.

[EDIT]: I disabled HT in the Bios and now I have more headroom on the CPU.
I did test with or without HT very often in the past, never noticed any difference so I let it enabled. But now is HAS to be disabled otherwise I can’t play my larger projects anymore.
So there must be a defintive change in the 10.5.20 update concerning this.
But I’m glad I can work again…