I don't notice any frame drops in FSX either and I've got 5 instances (!) of Plan-G connected (SimConnect). One instance at the PC running FSX and 4 other PC's in various rooms are connected. 
(FSX PC is a W3520 running at 4.3Ghz.)

First of all, thanks for a magnificent add-on! I use it mostly for flight monitoring, following the flight from everywhere at my home. Great!

And then to my humble request;
I would really appreciate if Plan-G could open pdf's.
If I add (to some predef. directory/folder) the charts (rwy appr, stars, sid etc) of an airport in the pdf format with a defined naming standard (ex. ICAO-RWY.pdf) then Plan-G could open the default pdf reader with that document(s) when left-clicking on the map or maybe when clicking on the rwy (or other stuff) at the info pane.

The idea is to use Plan-G as my only in-flight information tool (it's pretty close as is).

Thanks again for this beautiful software.