In answer to my own question - the system works very well, stable. No crashes in AC10, fast opengl. Renders faster - can't say what
actual speed increase though.
Only minor complaint is wireless mouse/ keyboard sometimes gets "lost" so press reset button and all OK
[EDIT]
Our system was very sluggish initially. Tracked it down to the Microsoft wireless keyboard and mouse being interfered with by our D-Link wire router (despite our IT guy saying this can't happen). Changed to corded mouse/ keyboard. The next issue is that the antivirus software scans in background which slows the system down. AVG is apparently not optimised for Dual/ Quad systems. Stopped it and now the system is fast.
Now if only Archicad could use the Dual/ Quad core more effectively in normal operations ( as against layout updates and Lightworks renders) ...
