Effectivnes of making a custom Windows Vista installation
Because I often use Windows and it often likes to break, I decided to build my own installation image, which includes all the updates and can be used out-of-the-box. The operating system was installed using the official Windows Vista Business DVD x64 with sp1 included.
Process
I found essentially two ways of getting the system have Service Pack 2 installed -- using Windows Update and standalone installer.
Firstly, I installed all available updates using Windows Update, the WINDOWS folder had 26GB in size. I also installed 1GB of applications which I'm going to add to the calculation. The rest of the install was default.
Then I used imageX to build the image
imagex /compress fast /check /flags "VISTA BUSINESS" /capture G: F:\install.wim "Windows VISTA BUSINESS x64" "Windows VISTA BUSINESS x64"
Where G is the drive with windows and F is the data drive.
The compressed WIM came out to be 10.1 GB big, which seemed a little too much to me, so I decided to try again.
Second try
I only installed raw Windows Vista Business Service Pack 1, then installed Service Pack 2 using the standalone installer and all of the available updates via Windows Update. The resulting WINDOWS folder size was 18 GB. It was also helped by removing service packs' (un)install files, which saved about 1.8GB.
Removing SP uninstall files on windows vista: - SP1: vsp1cln.exe - SP2: compcln.exe [source: https://kb.wisc.edu/page.php?id=22515, 2015-02-04]
ImageX was, again, used to build the image:
imagex /compress maximum /check /flags "VISTA BUSINESS" /capture G: F:\install.wim "Windows VISTA BUSINESS x64" "Windows VISTA BUSINESS x64"
Where G is the drive with windows and F is the data drive.
Results
Overview:
Compression WINDOWS size ImageX time WMI size fast 26 GB + 1 GB 58 minutes 10 GB maximum 18 GB 68 minutes 5.6 GB
In practice:
Fast compression does ~0.47 GB per minute.
Maximum compression does ~0.26 GB per minute.
Fast compression is ~57% faster than maximum compression.
Fast compression has a compression ratio of 37%.
Maximum compression has a compression ratio of 31%.
Conclusion
The whole installation of the second try has taken approximately 7 hours. While this might seem long, it is far less than installing windows usually takes (a day). It also doesn't require an active internet connection to install the updates on the target computer.
I know Windows Vista is old and the ratios might not apply to new versions of Windows, however, I dare to expect that the algorithm used in WIM files was only improved.
I encourage anyone with sufficient technical skills, patience and courage (the latter is more important, though) to build their own Windows installation, especially in case their system tends to break several times per year and they don't have the will nor need to use full copies for backups.
PS: I unfortunatelly cannot publish the finished version due to Microsoft's licensing conditions. (And slow internet upload speed)
PS2: Yes, I use Windows Vista, it fulfills the purpose for my windows-related experiments and as I already own a valid key, I have no need to upgrade just because of the "Vista is bad" stereotype. I have never had any problems with it, excluding the problems commonly pointed out by Windows users with FOSS background & experience.