When you download the update from MSDN, the first odd thing you’ll notice is that what shows up as a result is a ZIP file. Upon expansion, this is what the 64-bit version unpacks into:
Update 1 turns out to include 6 standalone installer update files (.msu)
The ReadMe.txt file is actually important because it lists the prescribed order of installation for the files in this collection. Based on the last 3 digits of each KB item involved that order is as follows:
1. 422: on both of my test machines (a desktop with an i7-4770K and a tablet with an i7-U4600) this item shows up as already installed
2. 355: this is the biggest item by far, at nearly 700 MB in size. It took 14 minutes to install on the desktop and 32 minutes on the tablet, including the time to get to a login screen after the restart required post-installation (all of the remaining items also require individual restarts, and are timed to get to a login screen as well).
3. 046: this took about 3 minutes on each machine to complete.
4. 592: this took about 1 minute on the desktop and 1:10 on the tablet.
5. 439: this took less than 1 minute on the desktop and 1:20 on the tablet.
6. 621: this took less than 1 minute on the desktop and 1:25 on the tablet.
Total time required varied from about 20 minutes on the desktop to 39 minutes on the tablet. It was kind of a pain to have to reboot 5 times along the way, but that’s what you must do when using the standalone update installer instead of waiting for Windows Update to batch those items together on your behalf. I’m guessing this will cut at least 6 minutes off the overall install time for users who wait to grab these materials from Windows Update next week.
One more thing: you’ll want to run the “Clean up system files” option in Disk Cleaner after installing these updates on a Windows 8.1 PC. This will recover about 700 MB of storage space on your boot drive (which may be meaningful for those using smaller SSDs to fulfill this role, as many systems do nowadays). The composition in the space recovered shakes down to about 690 MB of Windows Update Cleanup files on the 64-bit systems I updated plus a few other odds’n’ends (numbers will be lower for those running x86 versions of Windows 8.1 instead). Cleanup takes a while, too: about 35 minutes on the desktop, and 60 minutes on the tablet, by my rough measurements.