I have recently installed Ubuntu Mate 16.04 LTS on pi 3. But I am not getting 1920x1080 resolution. It boots up and covers the whole screen and everything looks bigger. I tried to change /boot/config.txt file by disabling # from the HDMI group 1 and 16 (under 16, I can't see 1920x1080, but it says 1080) but still the same. I also tried with Overscan option also. And I can see the screen changes and see the black border.I tried everything but still no luck. I am using 16gb Samsung SD card on Raspberry pi 3.
I also have another SD card with raspbian installed and I can able to get decent picture(1920x1080).
How do I make it work and get full 1080 p resolution?