Quick Answer

For the RTX 5090, ATX 3.1 is the better choice over ATX 3.0 thanks to its refined 12V-2x6 connector and improved transient spec. ATX 3.0 can run the card, but ATX 3.1 is the safer, future-proof pairing for a 575W flagship.

ATX 3.0 vs ATX 3.1 for the RTX 5090

Both standards handle GPU power transients far better than older units, but ATX 3.1 tightens the transient spec and standardises the more robust 12V-2x6 connector over ATX 3.0's 12VHPWR. For a 575W RTX 5090, that improved connector and margin matter.

An existing quality ATX 3.0 unit will run the RTX 5090 fine, so this is not a reason to replace a good supply. But if you are buying new, ATX 3.1 is the obvious pick for the cleanest, most reliable connection.

Choosing Wattage and Buying in SA

Pair either standard with at least 1000W for an RTX 5090 build with headroom; 850W works for a stock card but leaves little room. Confirm the unit ships with a native 12V-2x6 cable so you avoid adapters.

A quality 1000W 80+ Gold ATX 3.1 supply runs roughly R2,800 to R5,500 locally. Evetech stocks ATX 3.1 units with the correct connector for the RTX 5090, making the choice straightforward.

One last SA-specific point: factor in warranty length, in-country RMA turnaround and realistic stock before you commit, not just the headline price. A part that is a little dearer but backed by quick local support and proven reliability usually costs less over its life than a marginal saving on something harder to service here.

FAQ

Is ATX 3.1 better than ATX 3.0 for the RTX 5090?

Yes; ATX 3.1 refines the transient spec and standardises the sturdier 12V-2x6 connector. It is the safer choice for a 575W flagship.

Can ATX 3.0 power the RTX 5090?

Yes; a quality ATX 3.0 unit runs the card fine, especially at 1000W. There is no need to replace a good ATX 3.0 supply just for this.

What wattage do I need for the RTX 5090?

Plan for 1000W with either standard for comfortable headroom. An 850W unit works for a stock card but leaves little room for transients or upgrades.

Compare current power supply options with full local warranty and choose the one balanced to your budget and use case.