Windows updates and driver search consume massive amounts of RAM.

Solution 1:

This is a known issue with Windows Update. Microsoft fixed this issue with the update KB3050265 in June 2015:

Windows Update Client for Windows 7: June 2015
https://support.microsoft.com/en-us/kb/3050265

Fixes included in this update

This update addresses an issue in which system performance can be decreased during scans. This issue has the greatest effect on computers that have a small amount of physical memory.

Download and install the update Windows6.1-KB3050265-x64.msu.

Windows 8 also suffers this issue, but here the fix is to update to Windows 8.1, where the issue was first fixed before back porting the fix to Windows 7.

Microsoft released a new WindowsUpdate Client Update to fix the slow Update searching/Installation.

Installing and searching for updates is slow and high CPU usage occurs in Windows 7
https://support.microsoft.com/en-us/kb/3102810

Download:
32Bit: http://www.microsoft.com/downloads/details.aspx?FamilyId=fcd6bf5d-f004-4ca3-aa7e-1de462b91dd0

64Bit: http://www.microsoft.com/downloads/details.aspx?FamilyId=4fe566bd-31b1-4413-8c4c-412b52533669

Try this new Update and look if it speeds up the installation of Updates.

Solution 2:

Would the systems in question be fresh/not-updated-ever Windows 7? If yes, then:

1. Yes, that's how it works. However, this includes .NET updates, which require compilation of large parts of code on machine in question. There is a fix that raises priority of it so that computer finishes it in under an hour instead of several.
2. Only way to mitigate this behaviour I found to set update to "choose when to install manually". Unfortunately, it's just half-measure.
3. Not really. You can cut down on update downloading and installing drivers from manufacturer site, but that's about it.

This process got overhauled in Windows 8, so it's way less noticeable, but with windows 7 it's to be endured only.

However, speaking from experience, switching to SSD makes the symptoms to go away. For comparison: DELL e6400, fresh Win7 Pro install and full update took nearly 3 hours of constant churning. I basically left computer on automatic update (after another fresh reinstall) for the night after first update attempt resulted in killed processes. Same computer with SSD (850 EVO): update took bit under one hour and I could continue working on it.

EDIT: there is a reason why by default windows update is set on automatic for 3am...