Windows 7 64bit on an i7 3.4GHz 8GB ram,Sonar X2a no bitbridging all 64 bit plugs afaik.
'Rock solid' from X1 to X2 until X2a where it became 'totally un-useable'.
After much tweaking it is 'mostly stable'
What the hell happened with the X2a update I may never know?!?!
Quirks include a 4-5second delay after adding ANY vsti.
Screensets not switching, e.g. press 2 nothing happens, press 2 nothing happens, press 1 ( i'm already on screenset 1) then press 2 and it switches.
Here's hoping X2b sorts this all out.