Upgraded HDD but seems slow to boot

Any ideas.. Just got a Macbook pro 13" 160GB, carbon copied the drive to a 500GB 7200rpm SATA, all works fine though just seems to sit on the white screen at startup for a good 30 seconds before the spinning timer comes up to boot.. once booted, this drive flies.. just annoying that it takes a while to cold boot..

Anyone else seen this?

Scrub that.. just had search and seems its a common one.! selected the disk in sys prefs and restarted.. a whole 15 seconds to the logon screen! wow, what in improvement..