ATX 3.0 PSU Specification Loophole Lets Manufacturers Evade Stringent Excursion Tolerance Testing by Simply Excluding the 12+4 pin Connector

When screening new higher-end GPU launches these types of as the AMD Radeon RX 6950 XT graphics card, we observed some program reboots that triggered owing to electrical power-attract spikes (technically recognized as “excursions”). This is when a graphics card, for a short second, draws far more electric power than the connector is capable of supplying, triggering the PSU’s electrical protections, and resulting in a reboot. The new ATX 3. specification for the upcoming-generation of desktop Computer electrical power supplies empower PSUs with a higher tolerance for excursions, and prescribes screening standards to guarantee a PSU satisfies the ATX 3. spec. Aris Mpitziopoulos (crmaris) and Jon Gerow (Jonnyguru) uncovered wording in the most current Intel ATX 3. specification that could make you fork out nearer attention to testimonials of ATX 3.-spec PSU, when they’re out.

In a Components Busters report, Mpitziopoulos clears the confusion that the ATX 3. electricity source specs by Intel and the PCI-Convey 5. ability specification by the PCI-SIG, are mutually-inclusive—they’re not. An ATX 3. PSU is not necessary to include a 12+4 pin (or 16-pin) ATX 12VHPWR connector, irrespective of whether or not their nameplate Wattage is higher than 450 W, which signifies it can be subjected to passing less stress filled transient-response checks, specifically the capability to offer with a 200% tour for at the very least 100 ms.

The ATX 3. also introduces a element identified as Alternate Lower Energy Method (ALPM), which is hardware-stage preparation for OS-degree technique low-power device states, this sort of as Home windows 10 Modern day Standby and ChromeOS Lucid Rest. The ATX 3. spec experienced prescribed sure new keep-up time necessities for PSUs offering ALPM, even so it was found out that these specs only implement to the 3.3 V rail, and not the all-critical 12 V.

Put just, the vagueness in Intel’s specs enable the producer of a low-priced/mainstream PSU to assert ATX 3. readiness by excluding a 12VHPWR connector at any nameplate-Wattage, just so they can evade the steep transient-response tests expected to include things like such a connector. It lets them to [over]compensate with a massive amount of typical 150-Watt 8-pin PCIe connectors, and hope that individuals use cables included with their next-technology graphics playing cards that transform a amount of PCIe connectors into a high-Wattage 12+4 pin connector.

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