Whats your speed for fritzbox4040? Can i improve mine?

My setup is Vodafone Internet 1000/50 -> Technicolor TC4400 -> Fritzbox4040 with openwrt 19.7.7 -> Laptop(via LAN)

On the Laptop i can 250/50 maximal. i tried a speedtest package on the fritzbox which could get 250-300 in download. Upload speed is no problem at all.
I recently switched to the fritzbox4040, so i know that it was possible to get the full download speed of 1000Mbit/s. I also tested at weird times, like 2 am, 7am and 22pm just to be sure that its not a bad timing (running Cable).

I found some thread (Fritz!Box 4040 experiences - #2 by tomtom) where someone suggests enableing softaware nat offload, setting the CPU governors and installing irqbalance. I tried all of that but it doesn't seem to have an effect (the thread is a year old, thats why i didn't post there).

I did a factory reset on 19.7.7, but also tried 18.06 and the rc1 from 21.02 - all with standart configuration as well as the tweaks aabove. I mostly used the standart configuration. Rounter with NAT. No fancy VLAN settings.

Do someone get more than the 250Mbit/s download ? If so, what was your trick ? what did you do ?

Hi mac94,
I have a customized build running on my FB-4040 (Build for Fritzbox 4040, switch and LUCI working)
I have enabled "Software flow offloading" under Network --> Firewall and I have
echo performance > /sys/devices/system/cpu/cpufreq/policy0/scaling_governor in System --> Startup --> Local Startup
I'm reaching the maximum of 400 MBit/sec on my computer connected by cable. (I'm on Vodafone 400/20)
I can't tell if this setup is good enough for 1 GBit/sec.but I would like to here from you if it is.


Hi Tomtom,

sorry for the late reply. I tested your build and i got a whooping 900Mbit/s max transfer speed.
Though it wasn't easy, here is what i did:

  1. I started with a generic Fritzbox4040 image from openwrt and noticed my networkspeed is slow 400Mbit/s max on my 1000/50 connection. (19.7.7, 21.02, all seem to be slow)
  2. did a manual backup
  3. I installed your image from this post: Build for Fritzbox 4040, switch and LUCI working - #20 by tomtom and deleted all settings with it (as you said)
  4. I followed the post here: WAN speed on AVM FRITZ!Box 4040 - #12 by citydweller (Software Nat offloading + performance governor + irqbalance)
  5. Afterwards i enabled irqbalance in /etc/config/irqbalance via ssh by setting the option enabled to '1'
  6. Now i did another reboot.
  7. Here things get a bit tricky, i couldn't reproduce better speeds, I tried iperf3 as well as speedtest.net, the speed was constant. A few days later i tried to apply some pasive coolers to the CPU + RAM + SWITCH onboard. I used this video https://www.youtube.com/watch?v=a_l43SZChUY . But it might also be the HARD SHUTDOWN, and 5 minute waiting that did help (as all reboots before where soft reboots via luci)
  8. I verify my speed via the iperf3package. Searched a free server: https://iperf.cc/ (not all work, thanks for those who do). And used the following command to test my Download speed (as my Upload is only 50Mbit/s)
    iperf3 -c iperf.worldstream.nl -R -P 7
    multiple streams are important, as it seems like a single stream can only get you ~200 Mbit/s
    I also tried speedtest.net and got ~840 Mbit/s in Download

Thanks for the help. I hope it helps you thomas, I hope it helps anyone else on the internet and i hope you will update your image to 21.02 in the future :wink:

Hi Marcel,
thanks for the feedback, and yes, I'm currently working on a 21.02.xxx testbuild.
Could you do me a favor and disable irqbalance and test again ?
So we all would learn about the effect of irqbalance=1
I can not test this, as I'm "only" on 400/20 which is working fine without.