Linux Memory issue

[gopusrikar]

we have a problem justifying memory utilization by Linux servers.

See the out put of free :

free -m
total used free shared buffers cached
Mem: 7741 6839 902 0 56 527
-/+ buffers/cache: 6256 1485
Swap: 1027 0 1027

From above out put from 7741 of total RAM 6839 is used, 902 is free.
if we exclude buffers and cache from used then
6839 - ( 56 + 527 ) = 6368 - 112(not sure abt this value) = 6256

My question here is out put of free says 6256MB of memory is being actively utilized whcih is 80 %, but i don't see any process which is consuming memory.

out put of PS

ps aux | sort -k 6 -n -r | head | tr -s " "|awk '{print $1 " " $2 " " $3 " " $4}'
USER PID %CPU %MEM
PPPPPP 2753 83.0 12.9
root 2626 0.0 0.1
root 2265 0.0 0.1
root 2585 0.0 0.0
ntp 32452 0.0 0.0
68 2544 0.0 0.0
root 87 0.0 0.0
root 25121 0.0 0.0
root 2379 0.0 0.0
PPPPPP 25128 0.0 0.0

From above PS output it is clear that approx 13% memory is being utilized, but from from free it says apprx 80% is being used

Could some one justify this scenario?

[Rubberman]

A lot of that is buffered memory in the kernel, which 'free' and 'top' don't show. That will be given up as necessary when applications need it. Since 'free' indicates you aren't using any swap, don't worry about it.

[gopusrikar]

I think memory used for cache and buffer will be shown in free output, please correct me if i'm wrong.

And from free output which i have pasted in thread, is not using much of cache and buffering.

Do we have any other ways to find memory utilization?