I think the question is why does the same USB SSD appear 10 percent slower when connected to a Pi 5 compared to a Pi 4B?The obvious reason? Performance is limited by the slowest of:Raw SoC/CPU speed and RAM access speed have litle to no impact unless IO is entirely withnin the disc cache.
- Drive IO speed (writes are generally slower than reads)
- USB 3 speed and bandwidth
- PCIe bandwidth between SoC/CPU and controller.
viewtopic.php?p=2202700#p2202700
The USB controller on the Pi 5 is integrated in the RP1 which provides a lot of other functionality.
https://www.raspberrypi.com/news/rp1-th ... pberry-pi/It provides MIPI camera input and display output, USB 2.0 and 3.0, analogue video output, and a Gigabit Ethernet MAC; and it provides enough 3V3-failsafe general-purpose I/O pins, and the various low-speed digital peripherals, to drive our standard 40-pin GPIO header.
On the other hand USB on the Pi 4B is provided by an off the shelf VL805 PCIe controller.
Thus, the USB hardware on each Pi is different. I wonder if there is a driver or configuration change that could speed up USB on the Pi 5.
What happens if you boot the Pi 5 with the other kernel that uses the smaller page size?
Statistics: Posted by ejolson — Thu Mar 14, 2024 3:46 pm