Intel's ATX v3.0 PSU Standard Has More Power for GPUs

[harlan4096]

There is a new PSU standard from Intel, leading to huge changes in the IT market!

On February 1st, 2022, the ATX12V v3.0 spec became final, bringing considerable changes to power supplies. From now on, any PSU with more than 450W should include one of the new 12+4 pin connectors for Add-In Cards (like GPUs), and have various changes that allow it to deliver up to 200% of its max-rated capacity for short periods! 

The new ATX spec also ensures that there won't be any shutdowns and other compatibility issues with the upcoming generations of power-hungry GPUs. From now on, the PSU will be able to set the power limit of the graphics card, meaning that you should invest in the proper PSU for your GPU or else you won't get to utilize it fully! There are also some changes in the design and efficiency requirements of the Alternative Low Power Modes (ALPM), allowing for lower power consumption. 

The major changes that the ATX12V v3.0 brings are the following:

• New 12VHPWR connector for Add-In Cards (like GPUs) can deliver up to 600W
  
• The 12VHPWR should be labeled according to the maximum power delivered
  
• All PSUs with more than 450W max power have to have 12VHPWR connectors to meet the newest ATX spec.
  
• The PSU reports to the PCIe card, through sideband signals, its power capabilities, so the latter can set its power limit accordingly.
  
• PSUs should be able to turn on/off 175,200 times per year of their life without breaking!
  
• Changes in low load efficiency. Above 60% is required for 10W or 2% of max-rated capacity and above 70% is a recommendation.
  
• Increased tolerance for high power spikes, for the compatible PSU platforms. Up to 200% of the PSU's rated power for 100μs with a 10% duty cycle.
  
• Increased slew rates for transient loads (2.5 - 5x times higher for the +12V rail)
  
• 12V rail can go up to 12.2V to allow for lower voltage drops
  
• Broader load regulation limits for the +12V rail (+5 to -8% on the PCIe connectors and +5 to -7% for the other connectors).
  
• Changes in the speed of the Power On signal to allow for faster response and system's wake up, even when the rails are not at zero levels but somewhere in between. 
  
• Efficiency and design requirements for Alternative Low Power Modes (ALPM), previously called Alternative Sleep Modes
  
• The labels on the PSUs should include T1 and T3 timings, among others. 
  
• The addition of a new certification standard, Cybenetics, besides 80 Plus, is in the references section.
  

We will go through the list of changes explaining everything. We will try to keep things as plain as possible, but this won't be easy. 

Labeling, 12VHPWR and Form Factor Revision Updates

Labeling and Marking - RECOMMENDED

The PSU labels should including the timing values (T1 and T3) and any 12VHPWR connectors should be labeled according to the maximum power that is supports according to the SENSE 0/1 pins. In case the sense lines are dynamic, the product's documentation must describe the power levels supported based on the number of installed PCIe (graphics) cards. 

12VHPWR Cable Plug Connector

The new 12VHPWR connector is described in detail in the ATX12V v3.0 
Each of the six power delivery pins should handle up to 9.2A with a limit of a 30 °C T-Rise above ambient temperature conditions at +12 VDC with all twelve contacts energized. This means 662.4W in total with 12V output. 

The 12VHPWR connector's pins, except the four sense pins, have to use 16AWG gauges instead of the 18AWG required for the other connectors. The sideband signal pins should use 28AWG gauges. 

The 12VHPWR connector is optional for PSUs with 450W max power or less and is required for >450W PSUs. 
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