At work, I have four system with Windows XP SP 3 with 4GB RAM installed. When I start a lot of apps, I see that Windows gets unstable when more than 2.5GB of RAM is in use with the usual effects: Explorer crashing, icons disappearing.
So it seems that Windows runs out of memory even through at least 1GB of RAM should be free (as a 32bit OS, WinXP can't use more than 3.5GB max but I'm still 1GB short).
Another thing is that Windows is trying to extend the swap file (which is set to a fixed 512MB) which isn't exactly what I want. I know that XP tries to make my system more snappy by swapping prematurely (so it can simply free pages which haven't been used for some time) but I'd prefer a system which never swaps -- I do have enough free RAM.
[EDIT] My gfx card has 512MB and the mapping is FD000000-FDFFFFFF, E0000000-EFFFFFFF and FA000000-FBFFFFFF.
This means there is a pretty big gap between EFFFFFFF and FA000000 plus a smaller one between FBFFFFFF and FD000000. This is an NVidia GeForce 8400GS. Anything I could do here to move the maps? Or can I artificially unmap part of the gfx RAM? This is my development PC, I need no 3D at all ...
[EDIT2] My device manager says that free memory goes from 0x0100'0000 to 0xDFE8'6BFF which is roughly 3.3GB. So I'm still missing 0.8GB.