I live in a remote area where the mains voltage fluctuates all the time; the nominal voltage is 230 but can go as low as 150 and as high as 260.  Does anybody know whether the XPS 420 is or can be supplied with a psu that will cope with this situation?  Preferably of a higher wattage than is normally supplied.  I also do not know whether an auto switching psu maintains continuous low voltage supplies whilst it is switching.