memory problem

[ewed]

Hi everybody,

My memory problem view by "top command":
Initial state:
total --> 775 Mo
used --> 325 Mo
free --> 450 Mo

Final state:
total --> 775 Mo
used --> 760 Mo
free --> 15 Mo

I don't understand why my linux Mandrake Professionnal v9.2 (linux kernel v2.4.22 ) goes from the initial to final state as described above.
Remarqs:
- three days ago, I added a 512Mo DRAM memory (dane-elec) to the 256Mo already in the server (HP tc2120)
- The swap memory doesn't change (total=506Mo, used=0, free=506Mo)
- when I add all the memory size used by all the processes on the system in the final state, I find only 370 Mo!

The question: where are all the other ~400Mo ?

Can someone please tell me what to do, it's very urgent.

Thanks very much in advance.

[AndrewB]

I am not sure what the above babling says?
Basically you have added ram.. and your swap has not gone up?

Is that about right?
Thats all i can make of it?
Please rephrase.

If it is the above, SWAP is like virtual memory is on PPC, and windows.
It is a spare access memory location located on the hard drive. It is only used if all the RAM is used. Thus it is a bad thing as it runs at a slower access time.

Maybe give us the output of

 free

That shows us memory, swap and cache.

Thanks

[ewed]

The solution is found.
I believed on "top" but it wasn't the right command, it has another use(%CPU).

Actually, and you are right, the command "free" shows me where my potential memory has gone, it was buffered/cached and still free for the system( column-->"free"; line-->"-/+ buffers/cache" ).