On Tue, 21 Aug 2012 16:48:46 +0100, Percy wrote:

As I write my Windows 7 PC is within 500 milliseconds of UTC.

Mine probably is too. Once I installed W7 and let its own time checker
get on with it, I no longer needed to be arsed with the various time
checkers I'd used over the years - some of them quite good though. The
best was Dimension 7, which also acted as a timekeeper for other PCs
on my network.