Post A3FClEdFibMpyQ5hyK by kragen@nerdculture.de
 (DIR) More posts by kragen@nerdculture.de
 (DIR) Post #A3FClDGsmHsZkkcKSu by galaxis@mastodon.infra.de
       2021-01-14T23:12:33Z
       
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       Quick super unscientific storage test on the RPi 400: Write and read (after a reboot) 1GB of data with dd bs=1M to the included SD card and to a small USB3 stick on one of the USB3 ports.SD card writes at 15.5MB/s and reads 45.7MB/s. (Writing starts off at 19MB/sec but then gets slower with more data written).USB stick writes at 21.0MB/s and reads 97.9MB/s. (Write rate stays unchanged.)That still not great, but the system does feel slightly more responsive when running the system from USB.
       
 (DIR) Post #A3FClEdFibMpyQ5hyK by kragen@nerdculture.de
       2021-01-15T00:02:35Z
       
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       @galaxis I commonly see 500+ MB/s reported on SATA SSDs. I wonder if there's a bottleneck in the SD and USB interfaces, or if the devices there are just not optimized for performance?
       
 (DIR) Post #A3FGjYJ5zpbCEQ7Fq4 by galaxis@mastodon.infra.de
       2021-01-15T00:47:11Z
       
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       @kragen I'd assume they're mostly optimized for space instead of performance? The internal controller is probably a lot slower too, as well as the interface between that and the flash.That said, Jeff Geerling has done quite a bit of storage performance testing on various generations of Raspberries over the years: https://www.jeffgeerling.com/blog/2020/fastest-usb-storage-options-raspberry-pi