Almost all modern motherboards have a type c connector on the I/O Shield. I checked many manufacturers but they do not state how much power delivers through this tyoe c connector.

I know a normal USB2 port is allowed to delvier 500mA at 5V that is 2.5 Watts. I beleive for a USB3 type A it is 2A which means 10 Watts?

for the type C on the back of the motherboard, is it able to delvier lets say according to the spec 100 Watts, assuming a good power supply?

Is there a table for what can all these ports delvier and what are the limitations? I could not found any info gathered in one place.

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  • 1
    Im fairly sure USB2.0 can (often, not always) deliver 2 amps. While I am sure some USB-C ports can output large amounts of current, most cant. Many cant even be used for charging large devices like laptops.
    – davidgo
    Apr 20, 2022 at 6:28
  • 4
    100W is only for ports that claim PD (power delivery) compliance and is generally only found on power bricks. It is not a "standard" feature of every type C port. By default type c should be assumed to be simply a fancy looking type A port for power use.
    – Mokubai
    Apr 20, 2022 at 6:41
  • @Robert Please put that in an answer, ideally with a citation and a link.
    – gronostaj
    Apr 20, 2022 at 7:31

1 Answer 1


You have to differ between the maximum current a port can output in reality and the maximum current as it is defined by the USB standard. In reality, most USB ports can output more current than the standard defines but a standard-compliant device will not draw more power than the standard allows.

According to the USB standard the following limits apply:

  • USB-A port 2.0: 0.5A
  • USB-A port 3.0 (now called USB 3.1/3.2 Gen 1): 0.9A
  • USB-C port without Power Delivery (PD): 1.5 A or 3.0 A (the maximum current if negotiated between port, device and cable.

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