HI
As I understand it, Virtual Address Space is the working space for a program to run
on a PC. It does not have any relationship to the physical memory or page file on
your PC. VAS is a specific space that allows an application to run, and under a 64bit
operating system it is up to 4GB, and for a 32bit operating system it is 2GB, but can
be tweaked up to 3GB.
So from what I can see, everything we load into FSX, basically loads into VAS. That
can be aircraft textures, airport scenery, scenery textures, or else whatever you install
and run, and this is going to consume memory in VAS. Since we have a limited space
of 4GB, we have to be aware sceneries, HD aircraft textures, and so on take up a lot of
the VAS when loaded.
One of the biggest contributors to VAS usage, is how you have set your LOD_RADIUS in
FSX.cfg. This setting alone can offset the VAS usage by a couple of hundred MB when
bumped from default 4.5 to 6.5, and to add to the problem, FSX does not free up this VAS
space as you fly along,so if you start your flight with add on AC and HD scenery, this could
be up to 2.8GB VAS usage to start with, and as you continue your flight, this will slowly
grow. If you dont overfly any complex airports or scenery, you might get away with it,
but if you overfly any complex scenery, this VAS will continue to grow and you are likely
to get a OOM!!!, remember FS does not offload VAS until you close it down!
Since flying FS2004, I have always deleted the empty texture folder in my addon
scenery folder as I add my scenery in separate folders, and I understand that FS will
continue to look in that folder for textures as you fly and will not unload this folder
until you quit FS, this in itself will consume VAS memory.
I have also optimised most of my scenery and aircraft textures, and have
never had an OOM situation since I have been using FS2004/FSX/FSX-SE, have
a look at the "Mipmapping and Optimising Textures Guide" at the following link, it does
make a massive difference to FSX performance, it just takestime and patience, but it is
worth it IHMO
https://www.avsim.com/forums/topic/470865-guide-mipmapping-and-optimising-textures/
cheers