The RAM total of the apps "Running" never equals the "Used Ram" shown below on the scale I realised after a few days of observation, that the total of the RAM usage of indivisual apps shown in the running process is quite lower than that shown below it on the scale

And as "Cached Background Process" are calculated separately, they are not added in this "RAM Used" part of the scale.

Then what is using it? Coz the OS has its own space. Then what from the userspace is taking it up but not showing up?

Gingerbread 2.3.6

Like when I am writing this, the Total of indivisual values displayed is around 45-50mb while the scale below shows 95mb used!! How? \

Edit

Screen cast -

http://youtu.be/fzkQlZ8CdkU
I think it's because of linux. Linux put some disk cache on ram.
So, you can see cached ram, which is app cached ram, AND disk cached ram.
If you have access to a linux box, run free -m.

cubox@coruscant:~$ free -m
             total       used       free     shared    buffers     cached
Mem:          1974       1478        496          0        335        671
-/+ buffers/cache:        471       1503


Here, you can see that my server is using 1478 mo of ram. But, like 1000 mo is used for disk cache. You can't really recover it. If this part of ram is needed by the system, it's will not longer be used for disk cache and released for the app.