I've never bought any PMDG aircraft... how do they run? Are they very resource demanding? Similar to Captain Sim 757/767 in performance?
It depends on what plane you get.
The Beech 1900C/D have almost no impact on the frames.
The 737 is heavier, and the 747 is very heavy.
They're improving now though, the md-11 in my experience had much better performance over the 747, but still did slow down occasionally.
I think the new Jetstream is better than the Md-11 in performance.
I don't know how any of these compare to the Captain Sim, as a guess I would say favorably because the CS C-130 ran terrible on my rig and most posts seem to indicate the PMDG MD-11 was better on the frames...