castletonroad
Posts: 135
Joined: Sat Jul 25, 2015 11:23 pm

rpi4 network speeds: USB 3.0 vs gigabit ethernmet

Sat May 09, 2020 11:47 pm

Hi,

Can anyone point me in the direction of information detailing rpi4 network speeds over USB vs gigabit ethernet?

I'm interested to know whether I'm slowing my server's network connections significantly by connecting it to my LAN via a usb dock (so USB 3.0 connection), vs the gigabit ethernet port.

I certainly wouldn't do this on the rpi3, but wondered whether it's OK on the rpi4.

Thanks very much.
Raspberry Pi 4 Model B | Raspberry Pi 3 Model B | Raspberry Pi 2 Model B

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HawaiianPi
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Location: Aloha, Oregon USA

Re: rpi4 network speeds: USB 3.0 vs gigabit ethernmet

Sun May 10, 2020 12:06 am

The Pi 4B's USB-A ports are derived from a controller chip that's connected to a 4Gbps PCIe lane. So in theory the 4B's USB 3.0 is around 4X faster than gigabit Ethernet, in a perfectly simple world.

Of course there is interface and software overhead, and the four USB-A ports all share that 4Gbps bandwidth, so how much throughput you actually achieve depends on other factors. For example, if you have an SSD that's also connected to USB 3.0, it would take much of that 4Gbps bandwidth when active.

Probably not the simple answer you were hoping for.
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castletonroad
Posts: 135
Joined: Sat Jul 25, 2015 11:23 pm

Re: rpi4 network speeds: USB 3.0 vs gigabit ethernmet

Sun May 10, 2020 12:29 am

Thanks very much for the speedy reply.

That’s good enough for me.

I don’t notice a significant slow-down for my Nextcloud server on changing from eth0 to usb0, even though my server’s SSD (ext4) is also on the USB.

I’ll keep things as I have them.

Thanks for the info.
Raspberry Pi 4 Model B | Raspberry Pi 3 Model B | Raspberry Pi 2 Model B

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