A short time ago, Microsoft released a rather large set of updates in this latest round of Tuesday security and other fixes and changes.
While most boxes aren't seeing them yet, IT people and others may want to get this batch done.
Why? It's a significant update ..... and may be slow.
In most parts of the country (here in the US) you can manually go to Windows Update and get it done now.
The Windows 7 updates (totaling 9 on numerous Windows 7 boxes here) were faster than the older XP3 boxes (which ranged from 12-16). Some had to be rebooted twice. Hint: Do the optional updates after - if you need them.
Overall, it wasn't the size of the downloads. The .Net framework updates (and others) went right to the 'core' requiring a restart .... even by Windows 7 users.
On the two (older) Windows XP3 boxes here, the updates took 20-30 minutes to install (after the download).
Today's updates were anticipated and mostly deal with security.
If your system is set to auto-update, it's a pretty safe bet it will slow down a bit during the process, depending, of course, on your system resources.
Just a heads up.
If you allow Windows 7 to automatically update this time ... be prepared to see one of these :