Apple has released an update to its Leopard operating system, 10.5.5 that addresses a number of performance issues.

Highlights from the release include (via MacRumors)

- Addresses stability issues with video playback, processor core idling, and remote disc sharing for MacBook Air.
- Improves Spotlight indexing performance.
- Improves iPhone sync reliability with iCal and Address Book.
- In MobileMe: improves overall sync and Back to My Mac reliability.
- Improves Time Machine reliability with Time Capsule.

I’ve only just installed it now, and first impressions are all good. The biggest difference I can see immediately is that finally Spotlight has been fixed. For me, it meant often waiting as long as 4-5 seconds for Spotlight to find a program or document after I’d typed the word. With 10.5.5, Spotlight starts showing choices from the moment I type the first letter, and the whole word isn’t required, or if it is, the result is immediately available.

A full list of the changes are available on the Apple website here.