well, i'm not 100% if in your case other mobo will solve the prob., in mine it has...
about sts sampler, i have it installed, but didn't use it much so far, but i can try next time

have nice time
I don't know what you mean by "your controller" - my midi data come from the cubase midi track (I verified : there are only note on messages)... these things might help if you have eliminated active sensing from your controller and avoided midi loops in the use of the sts and cubase.....