I wouldn't worry about what Storage Manager is telling you. Storage Manager supports quite a few Adaptec cards using different technolgoies, and it may simply be that yours doesn't support that query.
I'd suggest checking you have the most up-to-date BIOS on the card, and also check if Windows needs any drivers.
I have an Adaptec RAID card. In RAID-1 it isn't as quick as my primary SATA drive, but it's certainly not that far behind. Unfortunately, my system runs Linux and I have no experience using it with Windows.