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My motherboard has a slot on the motherboard for,

JPI2C1 Power Supply SMBus I2C Header (X13SAE-F only)

What is this used for? The motherboard manual say nothing more about it. What is this for? What do I plug in there? What happens if I plug nothing in there?

Evan Carroll
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1 Answers1

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The system management I²C bus is used for various purposes, most commonly:

  • access DIMM SPD memory
  • access sensor information - temperature levels, fan speeds, voltage levels
  • control fan speeds
  • smart power-supply management (fan/temperature/voltages)

There may be vendor options that connect to the I²C header - either additional monitor/actor chips (case temperature sensors, smart PSU monitoring), or optional monitoring or management like IPMI / lights-out management. There may also be third-party options that you can plug in and use. There's no need to plug in anything though.

Workstation and server boards may use multiple I²C busses.

Zac67
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    doesn't answer What do I plug in there? What happens if I plug nothing in there? – Evan Carroll Jul 25 '23 at 14:52
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    @EvanCarroll I thought it became rather obvious - I've added some text just for you. ;-) – Zac67 Jul 25 '23 at 15:03
  • I'm not sure how it's obvious when something says "Power Supply SMBus" I think it needs power and I'm wondering what kind of power I need to provide it. But thanks. – Evan Carroll Jul 25 '23 at 17:24
  • My educated guess is that you can plug in a management cable to a smart power supply to monitor voltages, temperature or fan speed. Perhaps even for a redundant PSU. – Zac67 Jul 25 '23 at 18:34
  • If so, that information would make for a better answer. – Evan Carroll Jul 26 '23 at 22:28