pmdg freezes

Hi guys

I run fsx along with PMDG747 and ORBX YMML V2 while Im flying online.
Sometimes the fsx freezes and sometimes it doesn't. The graphic runs slow and I dont know why. and sometimes it says "run out of virtual memory"
It doesn't freeze when I delete ORBX and run the game at low graphic. But my coputer is capable of it and don't know how to tune it or set it up.

this is wat i have


i7-930 @ 2.80GHz
Gigabyte X58A UD3R
DDR3 6144MB and 539MHz frequency
NVIDIA Geforx GTX 460

any feedback is appreciated
thanks

FSX SP2 (or Acceleration) installed?

The FSX ability to address memory was patched in SP2.