I'm trying to figure out the differences. I have a new computer running Win10 64 bit that runs FSX flawlessly at max settings including scenery LOD at 9.5 and high frame rates. I run it with a UHD TV for a monitor and FSX set to match. It looks great. This is my work computer.

 

My old work computer is now my primary FSX system, running Win10 32 bit, which I need to run my TRC472 panel. Both have relatively cutting edge processors and comparable memory. The system running the 32 bit OS is plagued with OOM (out of memory) problems. If I run very low settings, it seems to be okay, but turning the settings up to something in the medium-high range means it will crash in under 20 minutes.

 

I can torture test the 64 bit system all I want, for hours, and it's fine. The 32 bit system can't seem to handle much at all, which makes no sense to me. FSX is 32 bit, so the 64 bit OS shouldn't matter, but it does.

 

I installed P3d v1.4 on the 32 bit system and it crashes even sooner than FSX. If I slew or fly at 160 kts or less with reduced settings, it crashes in a minute or so with the OOM error.

 

I had the TRC472 panel hooked up to an old Windows Vista system, which was serviceable, but slow. It didn't seem to crash at all. I didn't expect these problems with the more recent computer. I've tried eliminating the background apps in Win10, increasing the page file, etc and I'm only making a little progress. FSX will run a bit longer, but it's going to crash before I can complete a two hour flight. Any ideas?

Windows 32-bit can only handle 2 GB of VAS by default without any tweaks. The 64-bit Windows can handle up to 4 GB of VAS before it crashes (including overhead). That's why FSX & P3D crash sooner on your 32-bit OS.