Buying Guide
Sizing a Power Supply
The power supply is the part nobody thinks about until it fails, and the one most often chosen by picking a round number that sounds safe. Wattage does matter. It is also the least interesting thing about a modern supply, and on its own it will not tell you whether one is right for your machine.
Start From the Graphics Card
In a gaming machine the graphics card is almost always the largest single draw, and by a wide margin. A processor under full load, a couple of drives, the fans and the memory together often add up to less than the card pulls on its own. So the method that works is simple: start from the card, add the rest of the system, then leave real headroom on top.
Headroom is not waste. A supply run close to its ceiling spends its working life in the hottest and least efficient part of its range, its fan runs harder to compensate, and it has nothing left when the machine asks for a little more. A supply sized with room to spare runs cooler, quieter and usually longer, which is why we would rather size up a bracket than sell you something that only just copes.
Spikes Matter More Than Averages
This is the part that catches people out. A modern graphics card does not draw power smoothly. It draws in short, sharp bursts that can reach well above its rated figure for a few thousandths of a second at a time. Averaged over a second you would never see it. A protection circuit sees every one of them.
When a supply cannot absorb those spikes it does not fail loudly. It shuts down to protect itself, and the machine goes black in the middle of a game and comes straight back. People spend weeks blaming drivers and memory for this. The ATX 3.1 standard exists largely to specify how much of a spike a supply must ride out without tripping, which is why the standard a unit meets is worth as much attention as its wattage.
Efficiency, Cables and Noise
Efficiency. An 80 PLUS rating describes how much of the power drawn from the wall reaches your components, and the rest becomes heat in the room. Gold, Platinum and Titanium step that up in turn. In a cool climate this is mostly a running-cost question. In a warm room it is also a comfort one, and it compounds with everything else the machine is doing to the air around it.
Cables. Fully modular means you fit only the cables you use, which matters most in a small case where the space behind the supply is where everything has to turn. Also check how the card is fed: a native 12V-2×6 cable is one clean run, where an adapter is several older connectors bundled into one and is bulkier to route.
Noise. Many supplies keep the fan stopped entirely below a certain load, so the unit contributes nothing at the desktop and only spins up under real work. If the machine sits at ear level on the desk rather than under it, that behaviour is worth more than a small efficiency step. Our power supplies can be filtered by output and efficiency to narrow this down.
Common Questions
Can I keep the supply I already have?
Sometimes, and it is worth asking rather than assuming either way. Age matters as much as wattage, because the components inside age whether the machine is used or not, and an older unit may predate the spike behaviour of current cards. Send us the exact model and roughly how old it is.
Is a large supply wasteful in a small machine?
Not in the way people expect. A supply only delivers what the machine asks for, so an oversized unit does not burn the difference. Efficiency does fall away at very low load, so there is a point past which extra capacity buys nothing, but the penalty is far smaller than running a unit at its limit.
What is the 12V-2×6 connector?
It is the current single-cable standard for feeding a graphics card, and a revision of the earlier design with the contacts reworked so a cable that is not fully seated cannot carry high current. If a supply has one natively you plug it straight in. If not, the card comes with an adapter, which works but takes more room behind the card.
Tell us the graphics card and processor you are planning on, the case, and whether the machine sits on the desk or under it. We will give you a bracket and a reason for it rather than the largest number we stock. Availability and pricing confirmed at time of quote.