12 core system with SSD. Boot time has gone from 11-12 seconds to over 30 seconds. With each fresh boot most apps take ages to launch. Once they are launched and quit they reopen normally though. Play a movie. Sometimes there's no sound until I play with the volume keys. Sometime the sound cuts out until I hit a volume key again. From a performance point of view PB5 is much worse than PB4. The only improvement I see on the surface is that I don't get silly 'first time' warnings from apps when I log in.