Ubuntu 15.10 on a Dell XPS 8900 was freezing several times a day regardless of which kernel I used. Froze more frequently when I used dual monitors. Problem disappeared completely when I switched my graphics driver from Nouveau to Nvidia (clicked on Settings in Software Updater, selected the Additional Drivers tab then selected the latest Nvidia option).
Ubuntu 15.10 on a Dell XPS 8900 was freezing several times a day regardless of which kernel I used. Froze more frequently when I used dual monitors. Problem disappeared completely when I switched my graphics driver from Nouveau to Nvidia (clicked on Settings in Software Updater, selected the Additional Drivers tab then selected the latest Nvidia option).