No, as you know wim files are compressed, you can update all different editions (for a specified CPU architecture) in one wim and the size will be almost the same, because nearly all the files are the same.* If you mix X86 and X64 it will be bigger because a lot of files are different, but it will still be smaller than one x86 wim + one x64 wim. (* See also this old request, sadly still unfulfilled) @Stavros: why would you want to integrate a ton of updates in the first place ? Follow rhahgleuhargh's advice and use his list ! (or continue to integrate a ton of update and accept the fact that the ISO will be bloated). The point of updating a system, is basically for security purpose. I know, it is Windows, they will never be safe, but, why just intergrate updates that only make the WU think it is ok? Also it is a lot faster formating a machine in the same time or even 10 minutes slower, than waiting to download updates after a format. Specially when there is no good connection in my country.. I made this question because I want to make a multiboot usb stick with all versions of windows, and fully updated. But as i can see now.. Maybe I will make one usb for each OS of Microsoft.. Nevermind.. Thank you for your fast and accurate answers! Cya around!