I have the exact same problem... it's actually quite eerie.
I'm using the same HDD for booting, same OS, same RAID (5) for D:\, and the same thing happens to me. The only difference is I'm using a slightly different model raid controller (3114 instead of 3124).
I've reinstalled drivers a couple times and I am positive they are the latest ones.
Don, if you've found the answer that doesn't involve changing the power settings, I'd love to hear it!