Nice article, again. You mentioned BIOSes that move the mapped PCI memory to a very high address. Actually the Asus BIOS I have works the other way round: the RAM between 2 GB and 4 GB is remapped to 4+ GB.
I’ve recently upgraded to 4 GB because I’m dumb and curious and have too much money. Now I found that I have to enable this setting when running Memtest86 1.70 so that it can see all 4 GB. It will test them in to chunks: 116KB (or so) to 2 GB, and 4 GB to 6 GB, because that’s where the BIOS has mapped the second 2 gigs.
But for booting Windows (XP 32-bit) I have to disable memory remapping in order to get at least a measly 3 GB (the 8800’s video RAM takes up all the rest!).