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M.Blackmore wrote: >Why on earth do you need more? Only reason for changing is that if it is >always on machine you could get payback in a couple of years if you >were to go for a more efficient modern psu with a better oh darn the >words just slipped out of my memory, something factor... > Power factor!! My old one is a miserable .6, one of the modern ones is > over .8,<snip> Question is: are you paying for kWh or kVAh? I'm pretty sure it's kWh on domestic supplies. In that case power factor won't affect your electricity costs (assuming efficiencies are the same). AFAIK only large industrial supplies are charged by kVAh. For Paul >Ok, I don't know what you mean by .6 and .6, is this watts, volts ??? Power factor is dimensionless. It's the ratio between real power (power that actually does some work, which in the context of a computer basically means heat) and apparent power, which is VoltsxAmps. The discrepancy is due to energy storage in capacitors or inductors, both of which feature in decent power converters, which can be returned to the system and therefore doesn't do any work. See here for more info. http://en.wikipedia.org/wiki/Power_factor Basically, a power factor of 1 means all of the current flowing is doing work and that's the ideal situation in most cases. 0 means that all the current is going in and out of storage, generally slacking and not doing anything useful. -- The Mailing List for the Devon & Cornwall LUG http://mailman.dclug.org.uk/listinfo/list FAQ: http://www.dcglug.org.uk/linux_adm/list-faq.html