Intel updates ATX PSU specs, eyes PCIe 5.0 horizon

Major spec refresh includes 600 watt connector for GPUs

Intel has detailed new ATX power supply unit (PSU) specifications that it says are designed to support the demands of upcoming PCIe Gen-5 graphics cards, while also delivering greater efficiency.

According to the chipmaker, the new ATX 3.0 specifications are intended to "unlock the full power and potential of next-generation hardware", while Intel has also revised its ATX12VO standard that focuses on just delivering a 12V supply, aimed at improving efficiency by reducing a system's power draw at idle.

Most modern desktop PCs' power supplies conform to the ATX specification and the revised spec adds a 600 watt connector for GPUs.

In a statement, Intel claimed the ATX 3.0 specifications are the most significant update since the ATX 2.0 specs were introduced in 2003 to meet the expected power demands of the then-brand-new PCI Express interconnect.

One addition is a new 12VHPWR connector to provide up to 600 watts directly to any PCIe adapter card, with an eye on upcoming PCIe 5.0 graphics adapters that are likely to draw more power than existing PCIe cards, especially as GPUs get ever more powerful.

According to Intel, the new connector also supports sideband signals that will allow the power supply to communicate the maximum power it can provide to any PCIe 5.0 graphics cards. This has already been the subject of speculation that it could be used to lock down power supplies to specific products, but a more likely scenario is that a graphics card could limit its performance if a PSU is not able to deliver enough power, rather than risk a malfunction.

The ATX12VO 2.0 specification also adds a feature called I_PSU% to desktop platforms, which is a capability previously implemented only on mobile and server platforms.

According to Intel, this adds a telemetry pin to the PSU connector that allows it to report the percentage of total power being used by the system. The purpose of this is apparently to alert the system if power demand is at the limits of the PSU, allowing it to reduce performance and prevent the PSU from overloading.

Meanwhile, Intel asserts that the ATX12VO specification is going to play a vital role in helping the PC industry meet governmental energy regulations. The firm cites recently announced regulations such as the California Energy Commission's Tier 2 appliance efficiency requirements which require vendors to use extreme low system idle power levels to reduce consumption when the system is idle.

In its original specifications [PDF] for ATX12VO, Intel says it stands for "ATX 12V Only", and specifies a single rail power supply design capable of meeting existing requirements for power supplies while providing the opportunity for higher overall power efficiency. The idea is that any other voltages required within the system – such as 3.3v or 5v – can be generated by using step-down converters where needed, which is already common practice in many modern motherboard designs.

According to Intel, the new specifications should provide power and performance improvements across all desktop segments, from full-size towers to small form factor systems thanks to a smaller connector, more flexible board designs and improved energy conversions.

Intel expects the first power supplies and systems based on ATX 3.0 and ATX12VO 2.0 to be out later this year. ®