I just did a fresh install of Xubuntu 16.04 on my Lenovo X240. I got several problems just for doing that :
first one, I was unable to boot without nomodeset checked.
second one, I try first to just install xubuntu, for whatever reason grub intended to be installed on /dev/mmcblk0 but it failed, I was unable to close the popup warning me that grub failed... I was able to select another device/partition where to install grub, but I was not able to click on continue/proceed (I don't remember the word on the button)
then I booted xubuntu and try an installation trough the live usb. Same problem than above... I rebooted and then this time I specified, during the partitionning, where grub should be installed.
at least this time xubuntu was installed!
during the use of the live usb, I did not noticed any lag. But when I booted the fresh install... dudes, the wallpaper appears slowly from top to bottom, same when I click on the system-menu, the mouse moves slowly when it is over a window, or over the menu, etc.
I installed the intel drivers and I did run update. But still the same problem.
There is anything I can do to solve this before I install another linux distro ?