@sh809188 The speed stats are bogus?  Ugh...  that sucks.  I figured out that the Signal stats for clients are pretty meanless, but I thought the speed stats should be okay.

@Akaman  check your MTU settings

Verify with the provider docs if they suggest a value

Or make some experiment 

Tweaking the MTU settings I have achieved the max performances expected by the GPON fiber.

As  an impression or speculation  not backed up by  data , i think  that  or some update has nuked the default value for the MTU settings in the router...  Or simply that maybe  your (and  in the past mine) provider has activated some sort of tunnel at the trasport level so that the MTU non optimized causes fragmentation at a low level layers in the stack..

In my case Tuning the MTU has resolved.. 

@sh809188 

why do you think the controller does the speed test ?  the TL605 is doing it. 

A OC200 only has a 100MBit port , so it can't take the speed test and reach more tan that.

@mehmeh you're right, bad assumption on my part. 

I’ve taken some time to dig deeper.  

Upfront: I’ve decide to return the ER605 and keep the rest of the Omada setup. I found the VPN support of the 605 to be lacking and I also wanted more home features like parental controls. I like my old Synology 2600 router software and switched back to that (turned wifi off). Everything works well, so all good.

But while evaluating the ER605 I pulled together the following data that I could use some help interpreting.  (I also hope it might help others.)

Omada speedtest

• * I never had high internet speeds when view in the Omada Controller UI. Earlier in this thread it was mentioned that the ER605 ran the speeds tests.  They never were very high for my gigabit fiber connection, say 500-600mbps instead of closer to 900.

Raspberry Pi Speedtest

• I’m not sure if the my Raspberry Pi 4 is too underpowered to run speed tests. First, I can use iperf to validate hardwired ethernet speeds just find.  Second, I know it was mentioned that the Pi might be underpowered for encrypted connections.  That might be true — sometime the wget tests suggested didn’t get great speeds.   But…
• I think the biggest reason that speediest-cli didn’t report fast speeds when run on the Pi is because the servers it uses aren’t the closest.  When I run speedtest.net on a browser (note: on MBP) I can get my fiber speeds. For this test, I can see it connecting to a server in my locale. When I run it via the cli on the MBP or Pi, I get servers in different states. From what I can tell, the server list for the cli tool isn’t update to date and/or incomplete.
• The cli-tool result above was with common Python speedtest tools that I found and installed with `pip`. I had simply googled and found tutorials.
• When trying to find out how to get the local servers, I found that Ookla has their official tools here:  [Speedtest CLI: Internet speed test for the command line](https://www.speedtest.net/apps/cli)
• Now my Pi reports fiber speeds.  
• So, I guess, if you’re looking to have a cron job log your speeds on a Pi, I would get the official tools.

MTU

• MTU was bit new to me, but since it was mentioned as a potential problem I spent time check that too.  On my MBP, I used ``ping apple.com -s 1472 -D``.  Note the `-D` option, which I think is macOS specific.
• The result was 1472.
• Again, being unfamiliar with MTU I thought there could be a problem since ifconfig report 1500, but then I found this article saying you should add 28 because of header and packet bits, so 1500 is correct for my connection.
• [RT2600ac breaks HyperBackup (MTU Size?) | SynoForum.com - The Unofficial Synology Forum](https://www.synoforum.com/threads/rt2600ac-breaks-hyperbackup-mtu-size.6156/)

That was my sleuthing.  My internet works well so the family is happy. Maybe I’ll check out the ER605 again after the firmware gets more mature.

Thanks for everyone’s help.  
 

  @CLT-Geek having the same issues... tplink is bottle necking my internet. have tried everything firmware update ...factory reset and no avail. did you get it fixed?

  @CLT-Geek Same problem for me Piece of Crap

  @CLT-Geek Piece of Crap don't buy Piece of Crap likes this