It's odd that some of us using SSDs and squeaky clean installs are having issues.
I mean, I'm using a brand new Sammy 840 EVO SSD on a SATA 6Gb/s Port and still getting relatively poor startup/shutdown times compared to Win8Pro.
I'm loathed to reinstall Win8Pro again because I'm tired of having to resintall Apps and Programs and tweak them as I like them.
I'm just going to stick this one out as I primarily game and use Adobe suite on this rig and the benefits of Win8.1 are there enough to warrant stick with it.
I too would install Win8 again but this being a dual-boot configuration and having a $h!t-ton of programs and projects, I really can't afford to do it.