I am trying to run LFPG and LFPO from Aerosoft together, but on approach about 5 miles from LFPG, my fsx gives me an out of memory error. Is it possible to run these great sceneries together? Or does that hit the limit of what FSX was designed for?

I run both of these with FVFR HD Paris and the NGX. I have no OOM/VAS issues. But the secret is to have a slimmed down scenery.cfg when doing so....

 

You can use Scenery CFG editor to activate only the scenery you plan on using for a particular flight (for example your DEP airport, ARR airport and an Alternate.)

 

This is the best way to keep your VAS at a minimum is to have a slim Scenery CFG. And SCE is a great tool to do this quickly and effectively.

I always had OOM errors when using both these sceneries and the PMDG 737NGX however since switching to DX10 I don't have the problem any more.

I have OOM as well and I love it, its a must have for FSX.

DX10 fixer fixes OOM.