The Pi 4 launched with issues, including heat issues, but has been
improved. The improvements in power usage are supposed to reduce the
heat issues. A new bootloader was released. It includes that by default,
power will be maintained on the power pins, so power is maintained on hats.
https://github.com/raspberrypi/rpi-eeprom/blob/master/firmware/release-notes.md
https://www.raspberrypi.org/downloads/
There's a new tool for updating the Pi 4 bootloader EEPROM.
https://www.raspberrypi.org/documentation/hardware/raspberrypi/booteeprom.md
https://github.com/raspberrypi/rpi-eeprom
https://hackaday.com/2019/10/30/rpi4-now-overclocked-net-booted-and-power-sipping/
"The USB controller will get hot based on its usage now, instead of get
hot always. If you use it to its fullest it will get just as hot, but if
you don�t use it much or at all, it will be cooler."
"the bootloader (and associated firmware) actually reduce the power
consumption of both the USB controller and core SoC, with the USB
controller accounting for about half the power saving.
...
PCIe ASPM savings actually account for about half of the idle power
savings realised so far. Throughput loss to mass storage due to ASPM
appears to be in the ~2% range.
The rest is made up of SDRAM PHY optimisation, clocking improvements,
changes to the load-step response of the PMIC (allowing us to reduce
load-step margin on the core voltage). We also have a DVFS scheme which
makes the first (1GHz) frequency back-off much more energy efficient
than it was at launch."
Michael
On 02/11/2019 5:13 AM, David J Taylor via time-nuts wrote:
...
Just perhaps with a RasPi-4 you /might/ see an improvement as the
Ethernet has a more direct path, but that's a board where
self-generated heat is greater, so the thermal issues might make
things worse.
Try it and see!
Cheers,
David
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