Task manage performance memory used 3x as mush as listed under service

[robilong]

My Win7 PC run with 8GB memory without any remarkable problems over 2 years.
From time to time it run out of memory and asked to close Lightroom (using 1 GB) so finally I went to memory upgrade.
I installed 16Gb and now I noticed that Task manager performance memory usage doesn't match.
Under Task Manager services section including processes from all users total is 4 GB listed (I did some math)
But performance monitor states memory used 10.7GB. Where this 6GB goes?
CPU usage 10-15%
I have Norton Security active and would like to exclude any possible malware.

 

[townsbg]

A better way of looking at memory consumption is with process explorer. Please run it and post a screenshot. Process Explorer - Windows Sysinternals | Microsoft Docs