the higher model number of the sepron would indicate higher overall performance. however you may find the turon is moer suitable for a notebook for power and or heat reasons (im not sure on specifics so ill leave it to someone who is )
AMD prossors use a Hyper Transport bus rather than the traditional FSB due t there built in memory controller. where as the Intell platform still has its memory controller on the northbridge. so its more a matter of the design of these companats dictating the speed rather than a straight comparison between the 2.
and FYI centrino is a platform specifation combining a intel pentium m CPU, intell chipset and intel wireless networking, rather than sepron and turon that are just cpu's.