ATX 3.1 Explained — Why Your Next PSU Should Be Compliant

Intel’s ATX 3.1 standard is now the de facto baseline for new PSU purchases. The reason matters more than the version number suggests.

Headline change is the new 12V-2×6 connector, which replaces the 12VHPWR connector that powered the RTX 4090 generation. Pin geometry is updated, sense pins are pulled back, connector is rated to handle the same 600W power delivery — just safely.

Bigger spec change is transient response. ATX 3.1 PSUs must hold output stability through 200% transient spikes for 100 microseconds — which matches actual behavior of modern high-TDP GPUs under sudden load. ATX 3.0 (and earlier) PSUs would shut down or output dropouts under those spikes.