Thanks for the heads up SIW2,
As a side note it's good to see M$ thinking of the many users that, for whatever reason, decide to multi-boot operating systems,
A separate "boot" or "system" partition makes so much sense to cover the "OH dear!" situations that all Multi-boot scenarios sometimes cause.
I know it's been an option in Grub for a while now
Hopefully this system will be included in the RTM and later builds of Windows 7 and that they document it properly and perhaps even allow you to set-up this way when an existing partition structure already exists.
I do have a suspicion that this may well stop after the beta builds as M$ will assume that Multi-Boot is not a requirement with anything other than a Beta OS.
As for the use of registry defraggers or cleaners I personally would not advise they are ever used on a Beta operating system. This type of program, tend to be a bit too enthusiastic with what they consider dead links - often deciding that if it is not "normal" then it's not required. with a Beta OS containing many entries that were not "normal" when the Registry program was written it is , in my opinion, asking for trouble