you need to reduce resources being used in the background. Easiest way to do that is open MSCONFIG, and on the services tab, click the box for "Hide all Microsoft services", click disable all, and click apply.
This won't change anything with FSX when *memory* is concerned. It might help a bit with fps (or stutters) if there's a background program which is taking away processing time, but not memory, ESPECIALLY considering the users has 32GB of RAM, so I assume he uses a 64 bit OS.
The issue with FSX memory limitation is the absolute maximum of 4GB of addressable space for each single .EXE, which cannot be improved by closing *other* executables, because each one has its own *separate* address space, which can go up to 4GB, without any adverse effect on FSX usable memory.
The only memory that can be "saved" in FSX, is the one used by:
- Airplane models, gauges and textures. With some popular memory-hungry airplanes this is by far the most memory consuming item.
- Scenery. This can change a lot depending on the area and the addons installed there, and having a very detailed Manhattan scenery with all buildings AND a very large airport fairly close with TWO other big airports (LGA and EWR) nearby, makes it for a very critical zone.
- Under DX9, video memory allocated by FSX will be copied into system RAM, reducing the memory available to FSX, that's why it's best to use DX10 when short on memory.