Orbi limiting Raspberry Pi Bandwidth

Guru - Experienced User

Feb 16, 2020

I, also, have a Raspberry Pi 4B connected to Orbi. Mine is "headless", so I connect using SSH or VNC.

(The Pi 3B does not have "real gigabit", so maximum network throughput with a 3B cannot match a 4B.)

Spectrum modem --> Orbi --> Gig Switch --> Pi

The Pi 4B is capable of "speed". iPerf3 on the Pi registers 946mbs, which is about the limit of gigabit ethernet. That, of course, is between computers running on the Orbi LAN. How to test "speed" in terms of the internet? Booted into the Desktop graphical environment, connected with VNC and ran tests using Firefox and Chromium with speedtest.net and fast.com

Chromium always reports faster "speed" than Firefox, every time.

Fast.com always reports faster speed than Speedtest.net, every time.

Speedtest.net Fast.com

Chromium 118-130 180-240

Firefox 85-101 110-210

My Spectrum contract is for 200mbs, and my desktop/Android phone regularly report higher (236 this morning). My tentative conclusion is that it is not the Orbi "limiting" the Pi, it is the graphical interface on the Pi. I think Speedtest.net floods the screen with so many ads that it consumes more Pi resources than Fast.com, and that Firefox consumes more resources than Chromium.

This could all be clarified by using a non-graphical speed measurement tool. Perhaps someone knows of one?

The problem to be solved is "buffering" on video playback. I would investigate different video software or different video resolution.

CrimpOn
Guru - Experienced User
Feb 16, 2020
I did more tests on speedtest.net and notice that my Pi 4B starts out at "full speed" for about 10 seconds (above the 200mbs I pay for), and then the speed falls off sharply and ends up quite a bit less, but still in the neighborhood of 100mbs. My Windows computer does not exhibit this phenomenon. It stays at a pretty constant rate throughout the test. Android phone & tablet the same.

I struggle to comprehend how the Pi could be treated "differently" by the Orbi from Windows and Android devices. The Pi does respond to heat by dropping the clock rate. I am not confident how to measure for that effect while doing a speed test.

I did install Kodi, but "nothing happened" when I started it from the graphic desktop. Maybe it senses there is no HDMI connection on my "headless" Pi?

There are numerous posts on the forum questioning the Orbi's ability to deliver "full speed". Orbi was submitted to the FCC back in 2016, when 100mb speeds were rare, and I do not remember anyone offering gigabit to residential customers. Perhaps another test is to connect a computer to the switch and test speed with it. Does it achieve higher speed than the Pi? (Mine did.)

Sorry not to be much help.
- Duarditoh85
  Aspirant
  Feb 16, 2020
  When i use a computer connected to the switch i get Around 500/500. The only way to get Around 500 is to connect the Pi directly to the Nokia modem. If it goes directly to the Rbr50, i get Around 40Mb. Thats a big difference. Same cable used for both tests.
  - CrimpOn
    Guru - Experienced User
    Feb 16, 2020
    Thanks for doing the test. I am puzzled about the 40mb results. My Pi 4B gets over 100 with Firefox and almost 100 with Chromium.
    
    Amazon says 15mb will stream 4K video. Netflix wants 25mb. Both are a lot less than 40mb.
    
    It could be there are two issues:
    Why does Kodi buffer on the Pi?
    Why does the Pi get so much less "speed" when connected to the Orbi?
- CrimpOn
  Guru - Experienced User
  Feb 16, 2020
  Found a way to observe Pi cpu speed, and looks like that is "not it."
  watch -n 5 vcgencmd measure_temp
  where n is the number of seconds between observations. (I used 2). My Pi was at 49c when idle and "climbed" to 52c doing speedtest.net (55c for Firefox). The Pi 4B does not throttle clock speed until the CPU temperature goes over 70c. I cannot measure GPU temperature since my Pi is "headless".

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Orbi limiting Raspberry Pi Bandwidth