With 500-700 watt power supplies ranging from about £50 to more than £125, a big question for prospective PC builders is: how much do I really need to spend on a PSU? In order to answer that question, Hardware.Info put 43 different models from 22 different brands through their paces.

At the end of the grueling test circuit, several models had made the ultimate sacrifice, making one thing clear: you can spend too little on a PSU, even if it is not the most titillating bit of kit in your rig. Fortunately most of the contenders made it through the procedure, leaving us to interpret the results and pick the winners. Read all about it in Hardware.info's 17 page review.

Antec PSU

It may well be the most neglected part of any PC, the power supply unit or PSU as it is colloquially known. However, make no mistake about it, this modest component can either wreak havoc beyond belief on your beloved system or make it purr in absolute content. It all comes down to stability: can it deliver those much needed amps without having it voltage fluttering all over the place and just how clean are the electrical signals speeding towards your trusted CPU and graphics card?

You may think it is a subject for tech heads and white coats and you may well be right. However, if you are about to build your own system, you will still be grateful to the guys over at Hardware.Info who tested no less than 43 PSUs in the most common wattage range of 500-700 watts. Chances are the PC you want to buy needs a PSU in that range. So if you want to know for certain that you will be buying a raging powerhouse that can handle anything you throw at it rather than a sniveling mongrel that will burst into flames the first moment it is put under pressure, you had best head on over and do some reading.

As tests go, this one is comprehensive. The lab rats at Hardware.Info examined and catalogued physical features such as number of connectors and cable lengths (extremely dull until you discover you can only hook up one graphics card and your cable won’t reach the CPU power socket). However that is just the start, as after that they hooked up each and every one of these 43 square little boxes to 1600 watts worth of load generators and some seriously precise equipment to tell you in detail just how stable these things run, which translates directly into events that even your auntie who just plays solitaire will be interested in.

Such as how many blue or (depending on your flavour of operating system) green or grey crash screens your are going to encounter. Or how often you will experience random and volatile application crashes, spontaneous reboots or, that favourite of us all, smell molten plastic coming from your desktop’s enclosure. Ok, that last one is unlikely to affect your aunt but will be familiar to those who have overclocked their PC’s parts on a budget and lived to regret it

Just in case you are still not convinced you should know more about PSUs, here is one thing that will appeal to anyone: your choice of power supply directly impacts how much money you will be handing over every month to the utilities company. Pick the right one and you may well receive a tidy little sum (or at least enough for a few pints) by year’s end.

You see, there is quite a bit of difference in how efficiently PSUs convert the current they draw from the wall socket into the type your PC’s innards require. The best ones do it without spilling nary a drop, the worst ones are more like the quaffing Norsemen of yore, leaving up to 25% nowhere near where it’s supposed to land. In short, an efficient PSU saves money and which one is most efficient you can find out over at Hardware.info's extensive 17 page review.