this is correct
""" guess this is because the original Hyperthreading (Xeon, Pentium 4 if I remember correctly) wasn't that efficiently implemented by Intel."""
again I build and sell about 1200 systems a yr. a good 600+ are for pro audio. a large amount of those are for Cubendo.
DO NOT TURN IT OFF PERIOD
FYI we do complete integration. in other words before the system ships we install the interface and Cubendo and completely test it. (if you already own both)
and we completely support not just the system but Cubase(and other software) and the interface (or other hardware)
so this is not experience from 1 system but thousands of systems. been doing this almost 17 yrs.
if you are seeing issues from HT on your system is not built or tweaked or set up correctly. that simple.
there is a very rare nearly unheard of issue but that is another story. for 99.9% leave the HT alone.