GUIDE
ATX 3.0 vs ATX 3.1: what changed and does it matter?
Not much, for most people. If you have a good ATX 3.0 power supply, keep it. If you're buying new, ATX 3.1 is the current version, so pick that.
The short version
ATX 3.1 is a small revision of ATX 3.0, Intel's power supply spec. It swapped the 12VHPWR connector for 12V-2x6, cut the required hold-up time from 17ms to 12ms, and allowed brief power spikes through the graphics card slot. The big ATX 3.0 change, surviving GPU power spikes of up to twice the PSU's rating, stayed the same.
What changed
| ATX 3.0 | ATX 3.1 | |
|---|---|---|
| 16-pin GPU connector | 12VHPWR | 12V-2x6 |
| Hold-up time at full load | 17ms | 12ms (longer recommended at 80% load) |
| Power spikes the PSU must handle | 200% of rating for 100µs | Same |
| Spikes through the PCIe slot | Not allowed (5.5A limit) | Up to 13.75A (about 165W) for 0.1ms |
The 16-pin plug
On an ATX 3.1 unit, the native 16-pin socket and cable follow the 12V-2x6 layout: longer power pins and shorter sense pins, so the graphics card only gets the full-power signal once the plug is pushed all the way in. The plug on the cable itself didn't change, so an ATX 3.0 power supply's 12VHPWR cable fits and works in a 12V-2x6 graphics card. More on that in 12VHPWR vs 12V-2x6.
The 4 small sense pins tell the card how much power the cable can deliver. ATX 3.1 kept the same levels and added a new zero-watt state, so a card with its sense pins unplugged is told not to draw power at all:
| Cable rating | Typical use |
|---|---|
| 600W | RTX 4090, RTX 5090 |
| 450W | RTX 4080, RTX 5080 |
| 300W | RTX 5070, RTX 5070 Ti |
| 150W | Low-power cards |
| 0W (new) | Sense pins not connected |
The cable has to be rated for your card. A 300W cable on an RTX 5080 isn't enough, even though it plugs in.
Hold-up time
Hold-up time is how long a power supply keeps its outputs steady after power from the wall cuts out, like during a flicker or while a UPS switches over. ATX 3.0 required 17ms at full load. ATX 3.1 requires 12ms at full load and recommends longer at 80% load, which some reviewers see as a step backward.
In practice, a quality unit usually beats the minimum. If your power flickers often or your PC runs off a UPS, look for a review that measures hold-up time. Cybenetics reports include it.
Spikes through the PCIe slot
Graphics cards also draw some power through the motherboard slot. ATX 3.1 lets the slot's 12V supply spike to 13.75A, about 165W, for a tenth of a millisecond, instead of capping it at the old 5.5A limit. It brings the spec in line with how modern cards actually behave.
Should you replace an ATX 3.0 power supply?
No. An ATX 3.0 unit already handles GPU power spikes and has a native 16-pin cable. What matters more:
- Enough watts for your card and CPU. The calculator does this math.
- A 16-pin cable rated for your card: 300W, 450W or 600W.
- Age and condition. An old, noisy or out-of-warranty unit is a worse bet than the version number on the label. See signs your power supply is failing.
What about older ATX 2.x units?
Plenty of good ATX 2.x power supplies run modern cards through the adapter in the box. They weren't designed to the ATX 3.x spike rules, though, so give them extra headroom, especially with high-end cards. Can I use my old PSU with an RTX 50 series card? has a three-step check.
Buying new
Pick ATX 3.1. It's the current version, and Nvidia recommends a PCIe CEM 5.1 compliant power supply for RTX 50 cards, which is the graphics side of the same update. Look for "ATX 3.1" and "PCIe 5.1" on the spec sheet, and check that the 16-pin cable's rating matches your card.
Check your exact build in the calculator