1. Using WMIC commands
From command prompt type wmic memorychip get banklabel,devicelocator,capacity,speed
With this command, you can get very specific information like how many BANK used by your memory, how much the capacity and what speed the RAM is.
2. Using system from control panel
3. Using systeminfo commandSysteminfo will give more than memory information, it will include OS, model, install date. However if you want to get only memory capacity but not other information use this command:
systeminfo | findstr /C:"Total Physical Memory"