Speccy says 512, Windows XP says 256.

I have a very old rig, and I've been having problems with my ram slots, there was a time when the emitted a loud beep untli I interchanged them and put them back in. The beeping is gone but they no longer appear as 512MB at boot, but for some reason speccy says there's a total of 512 MB, even the task manager begs to differ.

Speccy is probably detecting the presence of the 256MB memory strip, however your system BIOS probably decided not to use it.

You could try memtest86 and see what information it finds about your RAM configuration and or any errors too.

Richard S.