That test was done with build 7000, the current official build is the Release Candidate or build 7100. When my system is just on the desktop with no programs running it used 20% of my RAM on build 7000 and 12% on build 7100 (if u didn’t take the time to look at my previous posts, I have 8 gigs of RAM).
I have run Windows 7 build 7000, 7057, and 7100 on my backup laptop that I use for gaming and work when my desktop is down, and it runs fine. My laptop is a Dell XPS m1710 formula red edition (i know its a little dated but its my backup) and it runs HL2 at 100fps at 1900x1200 with all setting maxed out except vsync with build 7100. The preformance and compatibility increase between 7000 and 7057 is big enough that its worth the hassle of reinstalling windows, but don’t expect to be blown away by the boost either. The increase also depends on what hardware your running aswell, like me for instance my desktop is pretty high end so gaming performance was pretty high to start out with so the increase was tiny. My laptop however is in the middle to low range area so the increase in performance was much bigger.
My laptop is nowhere near as powerful as that tho 
I’ll probably leave it like a month or so till I’m finished with uni, and then try it. I was always gonna upgrade, it was just a case of whether it was worth doing it soon. Performance sounds nice, but not essential.
