SP3 have now been added to Windows Update, and from all reports does make a difference in performance. A few people that I have spoken to have all said that boot times are reduced, and overall running seems to be quicker.

If you need to download it manually and/or hate windows update, here is a link to a page that lists the locations of the SP3 ISOs ready to download.

The most common/popular one will no doubt be the English ISO, so here’s the direct link from Microsoft for it.