I would guess that enabling the SATA controller uses up another IRQ therefore possibly causing IRQ sharing conflicts. Other than that SATA (Raided "0")is supposed to give better performance. From what I've heard and read.
The problem is that there are only 15 possible IRQ numbers and now motherboards use so many of them on built in things. You have to disable the ones you don't need. Most modern PCI cards are able to use the same IRQ as other divices but Creamware cards are different. This is a bad thing about Creamware.
it is as good or bad as with any other card and in noway CWA related.
If a mouse interupt isn't handled in time you won't even notice, if a harddisk is a ms late this is buffered, but a real-time audio stream MUST be serverd when it's due - otherwise you'll hear it