Fastest windows guest os?

[Leo W]

Hello,
I am trying to run windows guests on mac book pro 10.11.4 with 16G memory and i7 processor.
May I ask advices on which windows guest I should use to have fastest speed, the main windows apps I am using will be visio, expression web 4 etc, that can run from win xp to win 10. So Mainly, I would like to ask which one I should use among:

• 1) windows XP
  2) windows 7
  3) windows 10

Or further is there any general tweaks I can do to make the windows guest faster?
Many thanks for help!

[Leo W]

I have tested on my macbook pro with windows 7 and windows xp,
Windows XP still slightly faster to boot up (around 17 seconds)
Windows 7 takes 20-23 seconds to boot
my virtualbox is installed on external hard drive, so on SSD it might be different.