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Comment by heresie-dabord

4 days ago

In 2025, there are extremely efficient CPUs from Intel and Apple. Under 5W idle!

The old Intel CPUs were grotesquely inefficient. Every single generation of Raspberry Pi has been well under 5W idle. And just so it's clear, the author is using an old Raspberry Pi 3.

From TFA:

> The RPi 3B’s 19.2 MHz oscillator is physically located near the CPU on the Raspberry Pi board, so by actively controlling CPU temperature, we’re indirectly controlling the oscillator’s temperature.

Also note that the R.Pi can even be further optimised by switching off HDMI.

https://www.pidramble.com/wiki/benchmarks/power-consumption

https://www.jeffgeerling.com/blogs/jeff-geerling/raspberry-p...

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heresie-dabord

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nottorp  4 days ago

> In 2025, there are extremely efficient CPUs from Intel and Apple. Under 5W idle!

I don't think Intel has any "efficient" CPU that can go passively cooled at load though. Maybe Apple can do it for the low end SoCs.

The Pi 3 can go passively cooled and maybe even without a heatsink at load, but the newer Pis can't. Judging by the progression from 3 to 4 to 5, they will reach P4 levels of heat in the name of speed around ... 7?

> And just so it's clear, the author is using an old Raspberry Pi 3.

Yes, the author has harder problems to solve than what I'm whining about. But my concern is a bit related.

  • heresie-dabord  4 days ago

    > The Pi 3 can go passively cooled and maybe even without a heatsink at load, but the newer Pis can't.

    The Raspberry Pi 4 can be used without a fan. They are packaged inside keyboards, but both the Raspberry Pi 400 and the Raspberry Pi 500 are passively cooled.

    • nottorp  4 days ago

      I have a 4 with a huge ass passive heatsink on at home. It's my minecraft server when I feel like it.

      The heatsink is uncomfortable to touch (it's not in a case). Pretty sure it would downclock if i removed it. So it works without a fan, but not without a heatsink (I bet the keyboards have a heatsink for the Pis built in.).

      A 3 would have worked fine without any heatsink at all. At least at normal room temperature.

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