The Inq is reporting that there are a few oddities surfacing during early Conroe testing; one of which is RAID5 performance hiccups. They offer up a semi-explanation:

"It seems to us that Intel's Core 2 is suffering from a specific overhead when on-board RAID controllers are used. If you're unfamiliar with current on-board RAID5 controllers, let's just say that they really look like soft-modems and soft-sound cards, utilising power of the CPU for everyday work."