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Choose the Best Power Supply Unit for your Gaming PC in 2013

Updated on September 28, 2013
aa lite profile image

aa lite is a self-confessed geek and gamer fanatic who has put together her own gaming rigs for the past 15 years.


Don't Forget about the PSU When Choosing Your Gaming PC Components

When you are choosing components for your new gaming PC build, you are likely to spend the most time picking the best graphics card and processor that you can afford, but don't forget the humble power supply unit.

All the components depend on getting steady and adequate power from the PSU. Getting a low quality one will end in an unstable system that you won't be able to play games on.

Corsair CX Series 500 Watt 80 Plus Bronze Certified Modular Power Supply (CP-9020059-NA)
Corsair CX Series 500 Watt 80 Plus Bronze Certified Modular Power Supply (CP-9020059-NA)

Modular design. 85% efficiency. Long cables that make set up easy in large cases. Fairly quiet. Stable (ripple of 39.2mVtt at 500w)


How Powerful does your PSU Need to be?

The first thing that you need to consider are how much power all your components will need at full load. If you want a rule of thumb value, I would say you should get a 500-550W unit for a midrange build, like the excellent PSU from Corsair on the right. A 700-750W should be enough for a high performance PC, say with 2 graphics cards in SLI or crossfire.

If you really want to know an exact answer you can use one of the online calculators, like this one.

This is probably more than your computer really needs. However, remember that no PSU will provide all the power that it draws from a socket to your PC. A unit with 80% efficiency that draws 500W will only be capable of providing 400W to your PC.

The other consideration is that PSU's probably don't need replacing as often as graphics cards or CPUs. They frequently come with a 5 year warranty. You will probably want to upgrade most of your components in a couple of years' time, but your PSU will probably still be good to go.

80 Plus Level
Efficiency at 20% load
Efficiency at 50% load
Efficiency at 100% load

What is a Good PSU Efficiency?

Apart from the wattage provided, another distinguishing mark of power supplly units is the efficiency. This is important for two reasons.

PSUs with lower efficiency need to draw more power to provide your components with the wattage they need. Depending on how much you use your computer, investing in a more expensive, more efficient PSU could save you money in the longterm in electricity costs.

The other reason is that more the "wasted" power is dissipated as heat. An efficient PSU can help your system run cool

Many manufacturers now subscribe to the 80 Plus initiative, in which the PSUs are rated depending on their efficiency. The exact efficiency required to be certified at a certain level varies depending on the load. To achieve the basic 80 Plus certification, the unit must be at least 80% efficient, with higher efficiency required to achieve the bronze, silver, gold and platinum certification (see table).

Obviously more efficient units are more expensive. However you can get an excellent 80 Plus Platinum PSU, like the XFX Pro 750W for not much over $100.

How much do you care about the efficiency of your PSU?

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Other Considerations when Choosing a PSU

Other things that you need to consider when buying a power supply unit include:

  • Stability. This can actually be expressed quantitatively and measured if you have special equipment. The value is basically the amount voltage varies at high and low frequencies. For example you might expect the 12V line to always delver 12V. However the actual value might vary for 11.xx to 12.xx. These variations are measured in mVtt and the lower the more stable the unit. 50mVtt (a variation between 11.95V and 12.05) is very good. However, most manufacturers don't give you the numbers.
  • Modular Design This allows you to remove the cables that you don't need from the PSU, making cable management easier, giving you a neater build which is easier to cool. Sleeved cables are also nice. If you have a large case it is worth checking that the cables are actually long enough to reach all the components.
  • Noise Obviously a PSU that runs quiet is much nicer than one with a noisy fan. Of course other components will be adding their noise to the decibel level produced by your computer, but it is good to get a PSU that will not be adding much to the din. Hybrid fans can be an advantage here since they only turn on when a certain load is reached.
  • Durability Many PSUs are sold with a 5 year warranty, so really you should not have a problem with them suddenly giving up the ghost. However it is always worthwhile to buy with good Japanese components from reputable manufacturers, like Corsair, Antec and a few others. Even if you have to pay a little bit more.

Corsair AXi Series, AX760i, 760 Watt (760W), Fully Modular Digital Power Supply, 80+ Platinum Certified
Corsair AXi Series, AX760i, 760 Watt (760W), Fully Modular Digital Power Supply, 80+ Platinum Certified

92% efficiency. Modular Cables, and plenty of them. Very quiet. Supports Corsair's Link system.


A Few Recommended PSUs

There are several manufacturers known for producing high quality power supply units. These include Antec, Cooler Master, Corsair, Enermax, and Seasonic.

If you are building a midrange rig, and have a limited budget, then something like the Corsair CX Series 500W at the top of this page will be just right for you. You can of course find cheaper 500W units, but for this very modest price you get a modular design, 85% efficiency and nice long cables that will make sure that connecting it to everything is easy.

If you require more power than this, the FXF Pro Series Black Edition 750W is certified at 80 Plus Gold efficiency. This PSU is made by Seasonic, and is mostly indistinguishable from the Seasonic X series 750W, but is slightly cheaper. You can set the fan to either work all the time, or only at high load, which should help reduce noise. It has excellent voltage stability at full load, and operates quietly.

If you are after a premium product with this sort of power production, then the Corsair Professional Series AX760i is well worth considering. As you would expect at this price point it comes with platinum efficiency certification, and all modular cables.

It comes with a huge number of sleeved cables supplied, and is extremely quiet.

It also supports Corsair's Link software which allows you to monitor its performance and tweak the voltages to different components. Very useful for people who are heavily into overclocking.


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    • timorous profile image

      Tim Nichol 4 years ago from Me to You

      Good points. Generally speaking, with higher efficiency comes a tighter regulation of voltages, which are well maintained during peak loads. Some components like memory and the cpu are very sensitive to voltage variations. Especially the faster the speed of the system.

      The bottom line is, many fewer annoying quirks and glitches, whether you're a gamer or just doing your work. It's worth spending a bit more.