OSDev.org

I've recently pulled out some old pc's for testing (each one about 6 to 8 years old AMDs, homebuilt). Turns out all 3 of them are failing in exactly the same way. On boot it shows the ammount of memory it really has, then after a minute or 2 if you reboot it it sees only about half that (varies per machine, it is always a bit more than half the ammount, more like 60%). With the first machine I had the feeling it could be just a hardware failure in the machine itself, but out of the three machines I tried all three are showing the exact same symptoms. The things they shared during the attempts where: Location, a power chord connected to a 230 power socket, a keyboard and a philips monitor (flatscreen). Has anyone seen such a thing before and could the cause be in the environment???

Do they all have the same make of BIOS, and is it the BIOS that's telling you how much memory they have?

Nope, all different bioses.

what is in common is that all three are showing the problem after trying to install vmware ESXi 3.5 hypervisor. Is it possible for software to produce this kind of problem?

That's way outside of my knowledge. You still haven't said what it is that's telling you how much memory there is. Have you tried probing for memory to see if the amount originally stated is still there the second time?

Figured it out, bios was telling me ammount of mem btw. ESXi does some nasty tricks during its boot which on unsupported hardware can lead to all sorts of strange failures, including this one.