I too have the SATAII issue with a WD 500GB AAKS drive. Problem goes away as soon as disconnect this particular drive.

I've been in contact with ASUS and they've emailed me BIOS 0301. I tried this BIOS today (been using 0402 for the last week) and this still doesn't cure the problem.

At this point I would have to recommend that any of you guys looking to buy a P5K Premo don't do it. Stay well clear of this board until ASUS get this sorted