The final version of Vista SP1 focuses on under-the-hood improvements to reliability, security and performance, with very few changes made to the interface or Vista's features. Think of it as a giant, glorified set of patches and fixes rather than a clear and visible change to the operating system.

Although Vista Service Pack 1 won't be available to the general public until sometime in March, I received a copy of the final code and put it through its paces. My verdict? Don't expect many surprises from SP1 -- think of it as a big, glorified set of fixes and patches rolled into one.

As I've written about in a review of a beta version of SP1, the service pack leaves just about all of the operating system's features intact and targets performance, reliability and security. One fix -- the death of the so-called Kill Switch -- will be welcomed by many, as I'll explain later.

One of the biggest benefits Microsoft touts for Vista SP1 is faster performance, notably the speed with which it copies files to local disks and across networks. But on my test machine, copying to local disks and across networks with Vista SP1 is generally slightly slower than pre-SP1 and lags far behind Windows XP.

It's not clear whether my results will bear out when compared to many machines. Microsoft says, in fact, that its internal testing shows speed improvements of up to 50 per cent when copying files. So be aware that what you get on your machine may be dramatically different from what I found on mine, or what Microsoft found on its machine.