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PCIe 4.0 won't deliver 300W over the PCIe slot after all

PCIe 4.0 specification teased to deliver 300W over the PCIe port, but the information wasn't accurate - it won't do that

By Anthony Garreffa from Aug 26, 2016 @ 3:31 CDT

One of the biggest stories of the week was the tease of the PCIe 4.0 specification, which was said to deliver up to 300W over the PCIe port. It sounded impossible, but we thought the information was legit, considering it came from Tom's Hardware. The information wasn't accurate, with PCI-SIG coming out and confirming the real news: PCIe 4.0 won't deliver 300W over the PCIe 4.0 slot... damn.


The updated post on Tom's Hardware said: "Update, 8/24/16, 2:06pm PT:PCI-SIG reached out to tell us that the power increase for PCI Express 4.0 will come from secondary connectors and not from the slot directly. They confirmed that we were initially told incorrect information. We have redacted a short passage from our original article that stated what were originally told, which is that the slot would provide at least 300W, and added clarification:"

  • PCIe 3.0 max power capabilities: 75W from CEM + 225W from supplemental power connectors = 300W total
  • PCIe 4.0 max power capabilities: TBD

So it looks like 75W will be consumed from the PCIe 4.0 slot itself, but the limit of 300W might be increased. The PCIe 3.0 specification only allows 300W in total (75W from the PCIe 3.0 slot, 225W from external PCIe power cables), while the PCIe 4.0 standard might knock this up to above 300W, where 300W+ could be provided from the cables and the same 75W from the PCIe 4.0 slot.

Whatever happens, we're expecting more power - and higher bandwidth, and that's all I need to hear.


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