So, I wanted to get a quantifiable idea of how Windows 8 Pro performs versus Windows 7 Ultimate, which I was running. I ran a variety of free tests to try to determine this. One obvious oversight was timing how long it takes to go from a cold boot to opening Firefox. While I did forget to time that, Windows 8 is a bit faster. I do recall Windows 7 taking ~29 seconds to go from hitting the power button to opening Firefox in tests a while back. Windows 8 is accomplishing this in about 25 seconds. In both instances this is also counting the time it takes me to swipe my fingerprint to log in.
Machine setup:

Test results:

Any difference of 3% or less is what I would consider "noise" here. So, take the light green/red numbers with a grain of salt. Differences greater than 3% are what I am considering significant.
Quantitative Conclusions:
- 3D performance is the same (expected)
- 2D performance is a little less overall
- SSD performance is mostly the same, except for 4K random R/W with a queue depth of 32 (QD32) which was significantly lower. Honestly, I don't know what a practical interpretation of this would be.
- CPU performance in Prime95 is the same
- CPU performance in Passmark is better overall, probably because Passmark is newer and makes better use of Win8's multi-threading capabilities
- Memory performance is the same (expected)
- Win8 uses slightly less RAM (surprising)
Qualitative Conclusions:
- Win8 "feels" faster, in terms of boot and program loading
- The UI is smoother and pleasant
- The Metro interface is growing on me. Initially I was wondering why they "were putting a tablet UI in a PC OS" but that's not really the case. Metro is perfectly fine for mouse/keyboard usage if you make an earnest effort to unlearn some old habits.
- The UI just feels "cleaner" overall
So, I think that I will stick with Win8 from here. There have not been any compatibility issues yet. Now, there were a couple of oddities when it came to installing the Intel chipset drivers (you want the latest INF Update Utility, the Matrix Storage / Rapid Storage drivers are no longer applicable). Once I figured that out though, everything was A-OK!





