Same issue after upgrading windows 8 to 8.1 booting and shutting down very slow, before was couple seconds.
First day after upgrade was running good, today is very bad.
Also clean the windows old files, is that makes any difference?
MSI GE70, I7 4700MQ 2,4GHz , 12GB memory, HD 256GB Plextor PX-256M5M.
Update the bios, deep scan for viruses, clean the registry, update all factory drivers for windows 8.1, working fast, so far no issues.