I dunno how to account for it, but I'm seeing ALOT less disk access on my system that your describing. I installed multiple drives expecting to configure them for optimal disk IO but am having very little disk IO (other than when loading) with a single install on a single 7200k SATA drive. For my usage patterns, I would think a slower drive would only impact my loading screen duration. I saw ALOT more disk IO before my memory upgrade, which is the only reason I keep bringing that up.