On 28 July 2007, simon wrote: > I have recently installed centOS 5 on DELL pentium 2.7ghz (model > optiplex GX270) and have 512 memory I do not have a CentOS 5 box yet, Below is on a CentOS 4.4 box. A low end Dell Dimension 2400 (Celeron 2.6 GHz, with 512 MB RAM and integrated video and sound). I hope someone running CentOS 5.0 can reply to you! Check out the manual for the Optiplex (and the BIOS settings) and the Support area of Dell.com and maybe you will find out where the missing RAM is used. There's also a Linux area, in the Dell Support forums. Lanny > [mailing-lists at dell2400 ~]$ free > total used free shared buffers cached > Mem: 514440 511260 3180 0 22444 266204 > -/+ buffers/cache: 222612 291828 > Swap: 1044184 0 1044184 > [mailing-lists at dell2400 ~]$ cat /proc/meminfo > MemTotal: 514440 kB > MemFree: 2856 kB > Buffers: 22560 kB > Cached: 266208 kB > SwapCached: 0 kB > Active: 235784 kB > Inactive: 180100 kB > HighTotal: 0 kB > HighFree: 0 kB > LowTotal: 514440 kB > LowFree: 2856 kB > SwapTotal: 1044184 kB > SwapFree: 1044184 kB > Dirty: 8 kB > Writeback: 0 kB > Mapped: 165624 kB > Slab: 23660 kB > CommitLimit: 1301404 kB > Committed_AS: 521484 kB > PageTables: 2696 kB > VmallocTotal: 499704 kB > VmallocUsed: 3720 kB > VmallocChunk: 495604 kB > HugePages_Total: 0 > HugePages_Free: 0 > Hugepagesize: 4096 kB