The short answer
Get the right wattage from a well-reviewed model, and don't go cheap. The power supply feeds every other part, and a bad one can crash your PC or even damage it.
- WattageUse the calculator below. Most gaming PCs land between 650 W and 850 W.
- Rating80 Plus Gold (or Cybenetics Gold) is the sweet spot for efficiency and price.
- StandardATX 3.1 with a native 16-pin (12V-2x6) cable if you have, or plan to get, a newer graphics card.
- Warranty7–12 years on good units. A short warranty is a warning sign.
How many watts do you need?
Using the power ratings of the CPUs and graphics cards we trackThis is an estimate. If the graphics card maker recommends a bigger power supply on its box or website, go with that.
Why the headroom?
- Graphics cards spike. Modern cards can briefly draw well above their rated board power for a few milliseconds. A power supply running near its limit can shut off when that happens, which looks like a random crash in games.
- Power supplies run best at half to two-thirds load. That's where they're most efficient, coolest and quietest. Many stop their fan entirely at light loads.
- Upgrades. A little extra wattage lets you drop in a faster graphics card later without buying a new power supply.
- Too big is harmless, just wasteful. A 1,200 W unit in a 400 W PC works fine; you just paid for watts you'll never use.
Efficiency ratings (80 Plus)
| Rating | Efficiency at half load | Worth it? |
|---|---|---|
| 80 Plus (White) | About 80% | Only for very cheap office PCs |
| Bronze | About 85% | Fine for budget builds from a good brand |
| Gold | About 90% | The sweet spot for most builds |
| Platinum | About 92% | Nice for PCs that run hard for hours every day |
| Titanium | About 94% | Premium; the savings rarely repay the price |
Efficiency isn't quality. A Gold badge says how little power a unit wastes as heat, not how clean or safe its power is. Cybenetics ratings (and its separate noise ratings) are a stricter test. Independent reviews and community PSU tier lists are the best guide to build quality.
Connectors and cables
- 24-pin ATX powers the motherboard; every power supply has one.
- 8-pin CPU (EPS) powers the processor. High-end boards have two; make sure the power supply has enough for your board.
- Graphics power. Older and many AMD cards use 8-pin PCIe plugs (up to 150 W each). Most newer NVIDIA cards use one 16-pin 12V-2x6 plug (up to 600 W). An ATX 3.1 power supply has this cable built in, so you don't need an adapter. Push it in until it clicks and isn't bent sharply near the plug.
- Modular cables unplug from the power supply, so you only install what you need. Fully modular is the tidiest; semi-modular is a good middle ground.
- Never mix modular cables between brands or models. The pinouts at the power supply end differ, and the wrong cable can destroy parts.
Size and fit
Almost every tower case takes a standard ATX power supply. Many Mini-ITX cases need a smaller SFX or SFX-L unit, so check the case's spec sheet (see the PC case guide). Long ATX units (over 160–180 mm) can crowd the cables or drive cages in smaller towers.
Red flags
- "Peak" wattage on the box. A unit sold as "1000 W peak" may only deliver 600–700 W continuously.
- Unknown brands at very low prices, especially with no 80 Plus or Cybenetics rating.
- Warranties of 1–3 years on a gaming-class unit.
- Reusing a very old power supply with a new high-end graphics card. Units more than 7–10 years old may lack modern connectors and protections.