Cubase 8 Glitching + Odd performance Advice please.

First up… Love the new Cubase. im on Mac.

I have a heaps of questions.

First up im trying to make this cubase 8 work… i used 8.05 and the update was unstable for me.
any lists of known plug in problems
any supported video cards for cubase? im using dual screens, I thought maybe this is a problem…

mac pro video card common problems?

i was thinking maybe i should get this vienna pro thing…?? will it help??

Im having major problems with cubase 8 loosing asio timing constantly.

I reset the asio it may work for a while it drops again, the new thing wont hold it’s timing & major drop outs.

I have a Fast mac pro,it seems to be struggling with cubase?
12core mac 3.33ghz 16gb ram 1tb ssd.

I also opened it on my macbook retina & it’s the same glitching.

my cpu is dormant though.

im sticking to simple plugs. im using the fabfilter pro bundle & the bx digital stuff & lots of UAD.
I also use the uad box via Firewire…

Im using lots of Ni stuff to mix with & I noticed Guitar rig is playing havoc with Cubase & when i Click HI mode it locks cubase.

and lots of the cubase saturations or gates etc.

is there any known plug in issues? Fabfilter? im using a few groups, grouped into other groups.

im also get funny graphics issues the & a few lock ups.

I have done the format & have done the fresh instal…
I Swear it is either Gpu Problems or im really thinking a plug but could be a graphics issue also.

im not hear to bash cubase, I am having bad problems with it & i just want to work through it.