Ubuntu Server vs Desktop for mining PC
I would highly recommend using Ubuntu Server for this, as long as you know what you are doing without a GUI. Not having a GUI at all means smaller OS size and much less OS tasks. This translates into more power savings. If you are using graphics cards, a non-GUI OS will improve your mining performance. If using an ASIC/etc. you probably will not see performance improvements, but you should definitely see power consumption improvements.