Power Supplies

The power station behind a computer. Unfortunately, just like cases, it is often a neglected part when it comes to building a PC and is a massive corner cutting technique for the majority of computer manufacturers and system builders. Thankfully that is not the case here at UKGC as we strongly believe the power supply is the most important component of a computer. Unlike our competitors, we spend loads of time researching and testing power supplies (and all other components!) to ensure we are using the best in class. It is our strong opinion, the power supply is the least reliable part of a computer and if a power supply fails it can, and often does, take other components with it which is why we are so dedicated to making sure only the right power supplies go into our PCs. Corsair make the best power supplies, and have done for many years and are that confident they can offer great warranties like 5 years on the CX range and a whopping 7 years on the RM range - Not many brands even come close to this level of warranty. If any computer manufacturer does not state the make and model of a power supply in a system then stay away!

Essentially, with all our systems we have done all the hard work in choosing suitable power supplies and have ensured you can’t choose any upgrades that will be incompatible, so you need not worry, however if you are interested in the science behind it all and how other power supplies and other computer manufacturers can be potentially ripping you off then read on.

Exactly how good a power supply is, is mainly defined by 2 numbers - the Wattage (W) and the Ampere (Amps/A) available on the 12V rail. Many people think that the wattage is the only important number which is in fact simply not true; the 12v ampage is just as important and in our opinion more important.

Starting with wattage, you may think the more the better and to a certain extent you are right however this system is massively flawed as most manufacturers say a PSU is a certain wattage but it is in fact much lower than they advertise. If you’re lucky they will show a wattage spec with a "peak" wattage which means the power supply is capable of getting to that wattage but it will never be able to sustain a peak wattage - This "peak" rating is a good giveaway the PSU is not going to get anywhere near the advertised wattage. A budget brand, house brand or unbranded power supply may say its 700W but in reality, and is often the case, is only capable of sustaining of half of that output resulting in only 350W!

It is for this reason the wattage rating of as power supply can be massively inaccurate - The video below highlights this issue. This is why the Amperage of a 12V rail is far more accurate than the wattage and should be highlighted. A "Rail" is a power path within a certain supply which supplies a single voltage. A power supply typically has multiple rails that each power certain parts such as USB ports, PSU ports, motherboard logic chips, RAM, hard drives, CPUs and graphics cards. The important power hungry and power sensitive devices which include the CPU, graphics card, fans, RAM are all powered by the 12V Rail which is why it is only the 12V rail we are interested in rather than the 3.3V or 5V rail. Compare the Amperage of the unbranded/house brand/cheap power supply to a good quality PSU and you will see that the Quality power supply has a much higher Amperage despite the wattage being advertised as being greater. Feeding any component with fewer amps than it requires will starve it of power, resulting in faults and eventually total failure which usually comes to attention in the form or sparks and flames and a completely non working computer. Any manufacturer that does not publish the 12V Amp rail details will almost certainly be hiding the spec, and for this reason we recommend you avoid this kind of power supply.

Should you be interested in the science behind a power supply you can read more information in our How to choose a power supply guide.

The next rule of choosing a PSU is don’t push your luck! If you plan on popping in a meaty graphics card, extra hard drives and a couple of extra fans then upgrade the power supply! Always have more than you need, which will not only give you a 'safety barrier' but also room to upgrade and better operating efficiency. 

Just in case you’re not quite convinced about budget and below par PSUs check out this video, scary huh?