I have an old Lenovo Thinkpad that is one of my main laptops. It came with only 2 GBs of RAM and last night I increased that to 6GB. I set this laptop to dual boot to either Microsoft Windows 10 or Linux Mint 18.x.  I opened Window 10 and only 3GB of the 6.0 is used although it knows 6 is installed.  Linux on the other hand, uses all the 6 GB.  I am perplexed why this is happening.