Same here.
Tips I have for upgraders are.
Don't install Melodyne, Dim Pro, Rapture - Well I haven't and it worked fine just not listed in Command Centre. Well I'd be interested to see what happened with upgraders that did (which case ignore this advise).
Also clear your picture cache.
Look in Sonar
Edit-> Preferences and make sure it is all set correctly. The defaults may not take advantage of your system, and your file paths may not be optimal.
What I do (not a one size fits all approach):
Latest ASIO driver and it is selected.
MIDI devices enabled.
Use 64 bit double precision engine = on
Share drivers with other programs = off
Use mulitprocessor engine = on
(I untick the ASIO reported latency settings, some might not think it a good idea).
I turn off the automatic background as I don't need it
I have quadcore so I check ThreadSchedulingModel in the config file section= 2.
I keep an eye on the playback buffers in milliseconds when MIDI goes bad.
I turn off "always echo current MIDI track" as it confuses me.
Oh and I defrag all my drives after an install, and later on I do I full system backup (I have already done one before installation).
Ta..