'sqlservr.exe' is using 24 GB of memory which is the top on the list.

Also I noticed that the available memory has dropped from 4 GB to 1 GB when 'RamMap' app was started and then increased to 12 GB after 'RamMap' application was closed.

I see the following on event log while RAMMAP was running,

AppDomain 3 (DBXX.dbo[runtime].2) is marked for unload due to memory pressure.