My notebook is a Packard Bell Easynote S4810 with Windows XP Home Edition sp

It has on bord 512 MB of RAM, two modules 256 MB each.

Is there anyone that can tell me why if I run Msinfo32 it shows only
256,50 MB. ?

Note that:
- both Bios than Task Manager show more than 510,000 KB of phisical memory
- removing one of the two RAM modules the computer is much slower.

Thanks to everybody