What wattage power supply do I need?

Size the PSU around your graphics card. As a rough guide, a mid-range build is happy on a quality 650W or 750W unit, a high-end card wants 850W to 1000W, and an RTX 5090 build is best on 1000W or more. It is fine to leave some headroom, which keeps the PSU running cool and quiet. A 750W or 850W 80 Plus Gold unit suits most gaming PCs.

What do the 80 Plus Bronze, Gold and Platinum ratings mean?

80 Plus measures how efficiently a PSU turns wall power into PC power, which affects heat and running costs. Bronze is the entry level, Gold is the popular sweet spot for quality and value, and Platinum or Titanium are premium and most efficient. For most gaming builds, a reputable 80 Plus Gold unit is the one to choose.

Do I need an ATX 3.1 PSU with a 12V-2x6 connector?

Modern Nvidia cards use the 12V-2x6 (12VHPWR) power connector. An ATX 3.1 PSU provides this natively, so you avoid adapters and get better support for the brief power spikes a graphics card can draw. If you are buying a new high-end graphics card , an ATX 3.1 unit with the right connector is the cleaner choice.

SFX or ATX power supply, which do I need?

ATX is the standard size that fits most mid and full tower cases. SFX is a smaller unit for mini-ITX and small-form-factor builds where a full-size PSU will not fit. Check what your case supports before buying, since the wrong size simply will not mount. For a normal tower, stick with ATX.

How do I work out the right PSU for my build?

Add up the draw of your main parts, with the graphics card and CPU being the big ones, then add headroom and round up to a sensible wattage. A power supply calculator makes this easy, or you can use our rough guide: 650 to 750W for mid-range, 850 to 1000W for high-end, and 1000W and up for the very top cards. When unsure, a little extra wattage never hurts.

Is it safe to buy a cheap power supply?

The PSU is not the place to cut corners, because a poor unit can run hot, trip under load or, in the worst case, damage other parts. Stick to a reputable brand with an 80 Plus rating and a solid warranty. If you like to research first, a PSU tier list is a handy way to see which units are well built. A good quality power supply will happily carry over from one build to the next, so it is a sound long-term buy.