Cubase 8 Pro windows 8.1 glitching

Hi guys, I’m having a few problems running Cubase 8 pro on my PC.

I’m getting really unbearable glitching at only 5 or 6 instruments. I spoke to Steinberg who were very helpful but still the problem persists. I’m running quite a few inserts on some channels but nothing more than I have done on a previous cubase version running 32 bit. At least I was able to finish tracks on my last version but now i’ve updated everything it seems to have made things worse.

My new PC specs are as follows…

Intel i7 quad core
6GB ram
Windows 8.1 - 64 bit
Cubase pro 8 - 64 bit
Steinberg UR22 soundcard (2048 max buffer size)

I’ve tried disabling VST bridge (so now am only running 64 bit plugins/instruments) aswell as bouncing to audio, removing group chains, maximizing buffer size, activating asio guard and freezing instruments. These all temporarily fix it but after a while the projects begin to glitch out again rendering them unusable. I’m having the same issue with all my projects.

My previous PC was the same everything except running windows 7 32 with cubase 5 32 bit.

Here’s a list of my plugins & instruments
NI Komplete 10 (64 bits plugins) Massive & Kontakt mainly
Sylenth (occasionally)
Nexus (occasionally)
Fabfilter FX series (Pro-Q on nearly everything & alot of saturn)
Steinberg compressors, dualfilter, reverb etc.

Would be great if anyone has any ideas or experience with a similar problem and could shed some light on what may be causing these issues. I thought it might have been a plugin issue because i was running some 32 bit plugins before but even after removing them from the equation it’s still giving me trouble.

Thanks in advance