51–60 of 99 posts
That should give you 4-5x less drift than his results (though you could pair the techniques for even better figures)
The transmission site for WWVB has hundreds of water bottles to insulate the equipment from temperature swings. https://jila.colorado.edu/news-events/articles/spare-time
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I'm an old fart :) Intel tried to scale frequency up with the Pentium 4 in the name of performance, and it ended up extremely hot and power hungry. Just like some high end CPUs now, but then it applied to every model from Intel. I suppose you don't remember when a Raspberry Pi could run fine even without a heatsink, let alone active cooling. That's more recent than the Pentium 4.
It's already there really. It's heat output on the 4 and more so the 5 benefits from active cooling. The good news is the pi is practically pointless as a product for most people these days, and vastly better options are available cheaper, so unless you genuinely need the gpio theres little reason to buy one - very much their own fault for focusing on commercial applications but the Pi 5 as a product is practically p…
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> 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.
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.
The Raspberry Pi 4 will throttle performance at 80C (if I recall correctly) but it can work without a heatsink. I have a R.Pi 4 working without a passive cooler in an enclosure and it reports 55C-62C most of the time.
> I bet the keyboards have a heatsink for the Pis built in
You are right, both models use a heatsink. The PCB is also different, although the respective CPUs are standard Pi 4 or Pi 5.
Incidentally, the CPU in the R.Pi 400 has a higher clock rate than the standard R.Pi 4, so it performs better.
Instead of dedicating an entire Raspberry Pi with fancy pinning and temperature management by burning CPU time, wouldn't a micro-controller and a precise external oscillator fare better for time-keeping stability? I would assume that a STM32 discovery kit running a NTP server on its Ethernet port could probably do better.
RTLinux has a module feature to sync the scheduler to an external pin state. It is an obscure feature...
Adding more processors creates a well-known named-problem with metastability:
https://en.wikipedia.org/wiki/Clock_domain_crossing
Real-time is not guaranteed latency, and the Pi is not like Zynq fpga. =3
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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’…
> 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 aro…
Does the N100 not fit this criteria?
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> 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 aro…
> 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. Does the N100 not fit this criteria?