KDE 5

$ sudo apt-add-repository ppa:neon/kf5
$ sudo apt-get update
$ sudo apt-get install project-neon5-session project-neon5-utils project-neon5-konsole

On startup

raony@einstein ~ $ free -m
total used free shared buffers cached
Mem: 3680 1659 2020 16 155 673
-/+ buffers/cache: 831 2849
Swap: 19072 0 19072

After opening Chrome

raony@einstein ~ $ free -m
total used free shared buffers cached
Mem: 3680 2684 995 26 180 863
-/+ buffers/cache: 1640 2040
Swap: 19072 0 19072

Source: http://arstechnica.com/information-technology/2014/08/kde-plasma-5-for-those-linux-users-undecided-on-the-kernels-future/3/

http://www.tecmint.com/install-kde-plasma-5-in-linux/|