How to get the RAM Size of the computer using QTP/VbScript?

How to get the RAM Size of the computer using QTP/VbScript?

strComputer = "."
  
Set objWMIService = GetObject("winmgmts:"& "{impersonationLevel=impersonate}!\\"& 

strComputer & "\root\cimv2")

Set colPC = objWMIService.ExecQuery("Select * from Win32_ComputerSystem")

For Each objPC in colPC

msgbox Round(objPC.TotalPhysicalMemory/(1024*1024*1024),3)

Next