[SOLVED] Raspberry Pi 4 network speed slower than expected

Aug 10, 2019
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The Raspberry Pi 4 network speed I am getting is 645Mbps connected via Ethernet cable using speedtest from command line. I'm getting 950Mbps on my laptop with similar wired connection through switch/router. I expected the Pi 4 to have similar speeds of 1Gbps. What are the variables and/or troubleshooting I can try to achieve the higher speed like I see with my laptop. Any help is appreciated.
 
Solution
The RPI4 is not more susceptible for interference than other processors.
Its the very narrow distance between the 3 different network transceivers thats the problem.
(BT, WiFi and Rapoo)
They are constantly interfering with each other forcing retransmitting of error hit data packets.
Hence the appearent slow data receiving.

Try using USB extender cable to kick the Rapoo way off the RPI4.

For the internal BT & WiFi transceivers you may very well experience the same problems.
Try disable these internal device and use external dongles with extender cords separating them by one meter or so.
I'm having the same issue. I posted an article on the raspberry pi reddit page but didn't get any response there (I'll paste the post below). In short, I am getting a peak of 200-300Mb/s download before my CPU usage goes to 100% and my speed falls to about 50-100Mb/s. Uploads are not affected and I get at least 600 each test, most times in the 800's without the same CPU usage. Ethernet and wifi connection occasionally dropping for 1-3 seconds, intermittently. In my post below, I outlined the troubleshooting I did without success

Post from Reddit:
"I own a 3B+, run pivpn and get speeds of approximately 70/70mb/s when connected to the VPN (ISP speeds are gig symmetrical; connected via ethernet; VPN cipher is aes-256-cbc; CPU usage at 80% when speeds hit 70's and limits speeds from going higher).

I bought a pi 4B, anticipating I'd get a sizable network performance boost given the better CPU, 4GB ram, and gig Ethernet. Running browser speed tests through chromium, I'm getting a peak of 200mb/s down with speeds ranging from 20-80mb/s at the end of the test (with 100% CPU usage at peak) and 600-800mb/s up on average, peaking at 900mb/s (with about 50% CPU usage at peak). On the download side, there is a clear link between CPU usage and network speeds and I don't know what's triggering this. I've factory reset my router, used many different speed tests and servers, all with the similar results (I can list if need be). I have run vcgencmd measure_temp with nothing higher than 54C during tests. I'm running the latest version of Buster. Other ethernet connected computer (desktop) able to hit 950/950mb/s. I was wondering if anyone else had noticed this as well and had any troubleshooting advice. I don't understand how the upload can go much faster, using less CPU while the download is limited so harshly.

Additionally pivpn speeds on the 4B are 100/100mb/s. I was hoping for more, having read the OpenVPN Performance Thread and wondered if my above issue was contributing. I know the pi doesn't have hardware accelerated encryption, but with all of the improvements between the 3B+ and the 4B, I would've expected a larger gain in throughout speeds. In context, CPU usage is less than 25% during the VPN speed tests where I achieve the 100/100 speeds."
 
but why do others report hitting at or around 1Gbps on the RPi4? what is preventing these three examples from faster speeds?
I used my rpi4 for all of 2 weeks before switching back to the rpi 3b+ I was having the same issues however my do I 3b+ was much faster without oc even after oc'ing the rpi4 it got better speeds outta of it but still nothing compared to rpi 3b+ I think they just rushed productivity of the 4 and screwed something up between the brain and the other components. Because I looked In some places and people have no problems reaching reported speeds on it's release, however more and more are starting to complain that they aren't anything but a pile of paper wights essentially
 
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Speedtest.net (on the rpi chromium browser) artificially limits the up and down speeds.

I tried some other network tools and have come to the conclusion that slow results on Speedtest.net is an artifact of the tool and/or the rpi chromium browser rather than real results. Using terminal to run Speedtest-cli on the rpi4 ( same service, just from the command line) returns 900+mbps down, but like 4.0mbps up. Run on a rpi3b+, I see about 100mbps symmetrical. So, there’s obviously still some issue with the rpi4 upload speeds, but download seems more accurate. Either way, the results that these tools return should be viewed with a healthy dose of salt.

Tools like iperf3 might give more accurate local network results, but require a local “server” to send files to the client, and vise versa. You’ll just need to run iperf3 on your laptop, as well as, your rpi.
 
Now, maybe a different issue here but I am also getting very slow speeds on WiFi. Speedtest results are between 2 and 12Mbit down and up to 23 up. This is from within the browser as well as the speedtest command line. I do not see any cpu spikes. My laptop gets speeds of about 180Mbit down and 30 up, which is about my line speed.

I think that this also causes problems with watching youtube: stutters like crazy. I am hoping that my heatsink is in the way a bit and that reception will become better with a new heatsink/fan instead of the all aluminium heatsink that covers the pi right now (there is an opening for the wifi antenna though).

Compared to the RPI3+ that I have the networking is way slower and so is youtube on raspbian. Not at all what I was hoping for or anticipating!

EDIT:
After removing my Rapoo (2.4GHz) receiver from the RPI4 and putting it in a usb hub just 30cm away my WiFi went up to about 50Mbit down and 30 up! So it seems the RPI4 is way more susceptable for interference from other 2.4GHz devices then the RPI3. Works for me though!
 
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The RPI4 is not more susceptible for interference than other processors.
Its the very narrow distance between the 3 different network transceivers thats the problem.
(BT, WiFi and Rapoo)
They are constantly interfering with each other forcing retransmitting of error hit data packets.
Hence the appearent slow data receiving.

Try using USB extender cable to kick the Rapoo way off the RPI4.

For the internal BT & WiFi transceivers you may very well experience the same problems.
Try disable these internal device and use external dongles with extender cords separating them by one meter or so.
 
Solution
anyone find a better browser for speedtest? chromium definitely taps out at around 200Mbps and speedtest-cli upload speed doesnt get above 3.5 for me.

Tried in kweb but encountered same issue. Im using a pi 4 4GB.
 
EDIT:
After removing my Rapoo (2.4GHz) receiver from the RPI4 and putting it in a usb hub just 30cm away my WiFi went up to about 50Mbit down and 30 up! So it seems the RPI4 is way more susceptable for interference from other 2.4GHz devices then the RPI3. Works for me though!
Please dont edit old posts, as it makes it very hard to follow the flow of Q & A in a thread.
Instead always use a new post.
Thanks 😉
 
The RPI4 is not more susceptible for interference than other processors.
Its the very narrow distance between the 3 different network transceivers thats the problem.
(BT, WiFi and Rapoo)
They are constantly interfering with each other forcing retransmitting of error hit data packets.
Hence the appearent slow data receiving.

Try using USB extender cable to kick the Rapoo way off the RPI4.

For the internal BT & WiFi transceivers you may very well experience the same problems.
Try disable these internal device and use external dongles with extender cords separating them by one meter or so.
Youre answer is not even for the topic question.. have you read the topic question? the user have ethernet cable. The problem still exist for many users, including me. Your answer, marking the question as "solved" is not for the topic problem.
 
I know this is an old thread, but this may be of use: I recently got a Pi 4 connected direct to router via ethernet, and was also getting very slow speeds — Speedtest would report around 140Mb/s from the Pi, but 490Mb/s from router.

I fully disabled the Wifi on the Pi (adding dtoverlay=disable-wifi to /boot/config.txt then reboot, see https://raspberrypi.stackexchange.com/a/100549), and the speeds reported from the Pi are now as good as, if not better than the router.