I think the OP is saying memory used by sqlservr.exe per Task Manager (count on Processes Tab should include buffer pool for x64 SQL) is only 124MB but Task Manager Performance Tab is reporting 7.5GB of the 8GB of physical memory is used. Further to that, the majority of the 7.5GB is unnaccounted for in the Processes Tab.
I have seen this scenario reported before and the OP never got to the bottom of it: http://www.sqlservercentral.com/Forums/Topic1267628-146-1.aspx
@ananda.murugesan, did I describe the scenario you're reporting or am I missing something?
Either way, could you please run this from a PowerShell prompt on the affected server and post the results:
Get-WMIObject Win32_Process | Select Name,@{Name="WorkingSetSize(MB)";Expression={"{0:N1}" -f($_.WorkingSetSize/1mb)}} | Sort-Object Name
This will show us the list of all processes running on your server and how much memory each is using.
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