Ever since i’ve installed SP1 on my W7 64bit system the “Multi Processing” is broken in Cubase 5.1 
There is no difference at all whether it’s on or off. And this was working 100% before the installation. Guess i must move up to Cubase 5.5 to verify this.
Im running a Quad 6600 cpu and have tried several different motherboards with the same result.
Maybe it’s some vital setting i’ve missed?
/R