Losing sleep thinking about VAS!

Sorry for having so many questions in recent weeks, but I’ve upgraded my PC and have now learned a lot about OOMs, VAS, scenery management, etc. As a result, I’m having few crashes and better flights. But intellectual curiosity compels 3 more questions:

1. I've seen advice on FS forums that you can increase your VAS by:

(a) stashing high-maintenance planes in a new file (e.g., “Hangar”) where they will not be accessed by the sim and use up VAS; and

(b) disabling photoscenery that you will not be flying through.

The premise of this advice is that things in FSX use VAS even though you’re not actively using them. How is this possible?

2. Programs like TweakFPS purport to prevent OOMs by letting you select an appropriate config file, given your plans. Some of these save VAS by changing textures, resolutions, etc., and they seem to work – but in some cases, even while keeping your max FPS set at “unlimited.” Given that the human eye can’t really see any difference in frame rates much above 20, isn’t it ALWAYS a good idea to limit your FPS? If you’re cruising at, say, 150 fps, doesn’t that mean your video card is working to keep your FPS up at the cost of neglecting other stuff, like textures and resolutions?

3, I understand that available VAS declines over time in flight. Why? I have installed FSUIPC -- so at least I can now see when an OOM crash is imminent -- and I also see that VAS sometimes increasest, notwithstanding the downward trend. Why? Finally, the post-flight FSUIPC log always shows the minimum VAS as appreciably lower than the final on-screen number. Why? And which is the REAL number?

That’s all for now.

Thanks all,

Mac6737