bob prohaska  wrote:
> What is the I/O setup on the new Pi4? Is it like the earlier
> Pi2/Pi3, with a single usb hub supporting all traffic?
>
> I gather it has a usb3 port, but it's unclear what upstream
> bottlenecks might be present.

https://www.raspberrypi.org/documentation/hardware/raspberrypi/bcm2711/README.m
d

Bottleneck for operating a Pi 4 in general is overheating. It's bad. It's
idling towards 70 C in a fairly open Pimoroni case. I let the fan kick in
at 65 C which drops it to 55 C in 30 seconds or so. In a minute or two it's
back up to 65 C. Throttling would occur at 80 C which is easily reached
with any sort of load. A Pi 3+ in the same case with a tiny heatsink
(stick-on without thermal paste) idles at 50-55.

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