[MaKey]

> But what caused me to switch to a mac was the constant CPU and memory problems I was having with ubuntu.

Chances are that problem would have been gone too if you had switched to another device that isn't a Mac. If "kill the machine" means the machine getting incredibly slow then the problem might have been that the RAM was exhausted and your laptop began to swap - which could have been solved by upgrading the RAM or getting a device with more RAM.