- Having done so you’d want to provide a significant safety net in the form of a tolerance for miscalculation and possible future expansion: Therefore I would suggest that you multiply that figure you arrived at by 1.7, and buy a power supply of that wattage rating or as near it as possible.

Why 1.7? – Because that multiplier figure allows for significant expansion and upgrading of componentry in addition to a large tolerance in the event of gradual failure of your PSU because of age and wearing out.

(Please forgive the delay in answering; but there are other readers who might have chipped in their comment. I remind readers that this is not my blog, therefore I don’t maintain my contributions to it in the same way as I do with my own blog. – However if I do note a question posed in the comments on an article that I’ve contributed I will endeavor to answer it, at my convenience.)

Measuring the exact amount of power consumed will involve connecting a watt meter in series with every component while it’s running at full-power, noting down the reading, and adding up all the readings at the end of the procedure. – Rather time consuming.

Estimating a rough figure, on the other hand, is easier. Google for the maximum amount of power used by each individual component, add the figures up, multiply by 1.25, and get yourself a decent quality power supply that is rated at least 100 watts or more above that figure. – That should do the trick.

I find it curious that in every post I make; whether on my blog or on any other, you eventually turn up and try to rubbish everything I say. That behaviour is otherwise known as stalking and obsessive compulsive disorder. (OCD)

If you use a over-rated PSU, you *will* use more electricity. PSUs are typically most efficient at around 30-40% of their load capacity, which is what they will be idling at most of the time (if you knew what you were doing and bought the right wattage PSU).

If you had a high efficiency PSU (85%+ efficiency), but bought one twice as powerful as needed, you could be experiencing a very low efficiency of 70% or so, well off the peak of the efficiency bell curve – a big waste of electricity on a computer that may be on 24/7.

I understand if you don’t want to post up something like as too many people take it verbatem and it can potentially come back to bite you.

1000 watts, however, will be extremely useful if you’re planning to move to quad-SLI graphics or similar in the future. (Assuming you’re not planning to install them initially.)

If your system uses 500 watts but you install a 1000 watt PSU then the difference is 500 watts: This is what you’ll have spare.

What happens to this spare capacity? If your system draws 500 watts then at that point the PSU, despite being rated at 1000 watts, only actually supplies 500 watts – without a problem.

Will installing this PSU mean I draw extra power from the electricity grid and waste it?

No. Your PSU is capable of doing so but it won’t unbless you load it fully by adding a fair bit of extra hardware.

Since you have all that spare wattage available I suggest that you use it to power SLI graphics, RAID disks, extra fans, lights, gadgets and gizmos. There’s an article on my blog about some freaky gadgets that you might like to consider installing.

In any power supply worth buying, thermal compensation exists within the circuitry in the form of (a) thermistor(s) which read(s) the overall temperature as well as the circuit-board temperature and adjust(s) the output voltages accordingly, introducing a thermal compensation element into the internal voltage regulators.

Due to the large currents that are present within the PSU, this adjustment isn’t usually a particularly significant issue, and usually amounts at most to around a volt at most on the 12-Volt lines, millivolts with regard to the processor supply:

Bearing in mind that the resistance of copper track and copper wire increases only a minute fraction of an Ohm with each degree rise in temperature, also that a single Ohm will drop a single Volt at a current of a single Ampere; the unit would have to get very hot before any significant voltage drop ocurred, remembering that even at the 1 point whatever Volt supply to the processor you’d presently at time of writing be looking at a current of at least 20 Amps: An increase in temperature of several tens of degrees centigrade would then not even cause a voltage drop of 0.05 of a volt, and that drop would be thermally compensated for by the thermistor-driven circuitry in any power supply unit worth buying.

Any thermal cascade effect resulting from that adjustment would tail-off logarithmically within the next few millivolts above and would therefore be a non-issue.

Extra and more accurate thermal voltage compensation with a lower tolerance may be necessary at and immediately adjacent to the processor itself, where the temperature increase is greater as is the variation of such. – That’s a seperate issue, however, and is the responsibility of the motherboard manufacturer.

The best thing to do is to avoid the garbage PSU’s and to buy a PSU that’s rated well over the maximum power requirement for your computer….like at least 20%-25% more. The closer you get to your PSU’s maximum output, the more likely you are to get bad voltages, the shorter its lifespan and the more likely it is to fail and damage components.