The 2.5 Gig port of Orbi is limiting network speeds received by the ISP Modem

musicman0725, thanks for doing that.  Maybe it will get some traction in that arena.

Comparing my experience with the statement in your post, my wired speeds are consistent with the capability of the Orbi but wifi speeds are significantly diminished (200+ megabit) when the Orbi is connected to a gigabit port in the XB8 compared to the 2.5Gbps port.  It's just not enough for me to worry about right now.

Thanks again...

I don’t think any of us reporting in this thread are having diminished Wi-Fi speeds. It’s only on the gigabit eithernet ports, and only when connecting the Orbi to the 2.5 multi gig port on the Xfinity gateways

Yeah, it isn't impacting me either since I workaround it and only have the RBR850.  I'm just curious why it's happening.  Someone mentioned on the xfinity reddit I created that they had a similar issue until they disabled QoS on their tplink router.  They were also getting 400Mbps tops on the LAN ports of their 3rd party router with their xfinity modem.  I did not see a setting for disabling QoS on the Orbi.  However, there is a setting to disable WMM in the Advanced Wireless settings of the Orbi which is a QoS feature to prioritize audio, video and voice applications.  I have not tried disabling this yet to see if it would help.  BTW, when I connect to the 2.5mGig port both the XB8 and the Orbi show 2500M/Full as the link rate.  The Orbi also shows 1000M/Full as the link rate for all my LAN ports.  QoS or some sort of filtering sounds like a the culprit.  The speedtest from the Orbi itself (iOS app) gets max speeds when using the 2.5mGig WAN port on the XB8.  

Disabling WMM caused the LAN speeds to go back up to full 1Gbps when using the 2.5mGig port on my XB8, however, it also caused significantly reduced WiFi speeds on my devices (basically 25Mbps over WiFi).  This leads me to believe the issue is a software issue with the Orbi (also only the Orbi is impacted by this issue).  According to this thread, disabling the setting will also cause the Orbi to no longer support advanced WiFi standards.

https://community.netgear.com/t5/Orbi-Wi-Fi-5-AC-and-Orbi-with/Disabling-WMM-Disables-N-FW-V2-2-1-210/td-p/1666761

Not sure but the issue may be caused by QoS on the Orbi which doesn't appear to be configurable.  

Yes, lol.  I was so happy when I ran that speed test at first from my ATV and it was full speed.  Then I tested over WiFi and was like, okay this is way worse.  Rebooted the satellite I was by just in case that was the issue and it disrupted internet for everyone (normally rebooting a satellite doesn't take everyone offline).  Back to my old config and completely rebooted the system after getting the settings back to normal.  All good now.

HI musicman0725 you mentioned it disrupted internet for everyone, you may want to try speed tests etc with no one online but you - WMM prioritizes video and voice over normal IP traffic, so if people were doing things on the internet while you were testing, that could greatly influence the performance greatly. Your WiFi in a speed test will be lower priority than someone watching a youtube or netflix video. It's hard to do sometimes in a household, but testing without other people doing stuff is going to be much more reliable. 

Does the router component of the XB8 allow for WMM enabling/disabling? Sorry to ask, as there have been several users chiming in on their configs on this issue - which is the router - your XB8 or the Orbi? FWIW I have not seen any of this behavior with an Orbi router and a non-Comcast modem/router.

donawalt thanks.  Yeah, I definitely shouldn't have done this while everyone was using the system.  Updating settings on the Orbi hasn't really disrupted others before (i.e. changing the WiFi channel), however, after I changed the setting I rebooted one of the satellites and it disrupted people.  Right now I'm using the Orbi as my router, but I could always flip it and put the Orbi in AP mode.  I actually haven't tried that and think it might also resolve the issue but I prefer to use the Orbi as my router.  The XB8 is somewhat limited as a router (you can only configure it with the xfinity app and basically the only options it has are a DMZ and port forwarding) although it does support 6Ghz 160Mhz WiFi 6E bands.  My internet speed is the 1gig plan but I get closer to 1.2Gbps on a speedtest from the Orbi itself when using the 2.5GbE port of the XB8.  Of course that doesn't really matter since my overall speed of devices connected to the Orbi is slower.  Given that this model only has 1GbE LAN ports and WiFi devices will top out at around 750-800Mbps, I've been using the 1GbE port on the XB8 and connecting it to the 2.5WAN port on the Orbi which has been very fast and stable.

musicman0725 my experience turning off has been a little different...

With WMM off, my wired speeds remained low (around 350 Mbps) when the Orbi was connected to the 2.5Gbps port on the XB8, and they remained acceptably around 940 Mbps when connected to the gigabit port.   Like you, my WiFi speeds tanked in both scenarios.

I saw some discussion in the last few messages about having the XB8 in bridge mode and the Orbi in AP mode.  I typically have the gateway in bridge mode but tried it in router mode with the Orbi both in AP mode and router mode (a double nat no-no, of course).  In all cases, the behavior of slow wired speeds when connected to the XB8's 2.5Gbps port remained the same...

MontereyFred Thanks for testing that.  Yeah, not sure what the issue is.  I'm curious what putting a switch between the devices would do.  Unfortunately, I only have an extra gigabit switch and my only 2.5GB switch is in the garage.

Interesting, a 2.5GB switch placed between the gateway and Orbi might start to pin down whether this is an Xfinity problem or Netgear problem...

I was only able to test with a gigabit switch connected to the orange port.  It resolves the issue, however, the link rate is 1000M/Full.  Not sure what would happen with a multi gig switch.  However, if someone has one, they could see if it resolves the issue entirely, or at least if the issue only happens to the Orbi and not other devices connected to the switch.  

Wondering if anyone has a 2.5Gb or Multi Gig non managed switch they could test out? 

I ordered the Netgear MS305 2.5g switch (which is currently on sale) to replace my TRENDNet TEG-S350 2.5g switch in my garage as it has a known issue causing ghost satellites to show up in the orbi app (no other noticeable issues, but figured this problem was annoying enough to solve because it also causes the firmware update in the app to error out).  The new switch resolved the issue with the ghost satellites and so far is performing very well.  

I also tested putting the TRENDNet 2.5g switch in front of the RBR850 connected to the 2.5mGig port of the XB8.  This is where things get interesting.  The WiFi speed I got directly from the RBR850 was insanely fast (840Mbps).  Additionally, the LAN speeds from my ethernet backhaul SAT were only reduced to 700-750Mbps (instead of 450Mbps w/out the switch between the XB8 over the 2.5g port).  LAN Internet speeds directly to the RBR were around 800Mbps, BUT  speeds using a 1G usb-c adapter directly on the 2.5g switch was also reduced to around 800Mbps (getting the full 940Mbps when connected directly to any XB8 1GbE port).  Connecting a 2.5g usb-c adapter to the switch of course provided full internet speed (1150Mbps).  My conclusion is that although the 2.5g switch helps the Orbi, it actually has similar issues with the XB8 when connecting 1GbE devices to it (slightly reduced speeds vs using a 1GbE port on the XB8).  This leads me to believe the issue is with the Xfinity XB8 modem and not the Orbi.

How was the speed test on the RBR 850 Orbi itself?

The speed test on the Orbi app was 1150Mbps but speed from the RBR directly over a LAN port was around 830Mbps.  That same connection on the RBR850 consistently gets 940Mbps when using the 1GB port on the XB8 so using the switch is still a little slower with the XB8 and the 2.5g port.

I might add my modem is an XB7. Was going to upgrade to XB8 but looks like you are using the 8. Might try it anyway. 

gregnauman Yeah, I have the XB8 but since you already have the same issue with the XB7 it doesn't hurt to upgrade.  If the issue is hardware, you could get lucky and not have it.  If it's software (which I think it is), I'm sure it will eventually be fixed since it seems to impact more than just the Orbi.  The XB8 also has WiFi 6E which could be nice depending on how you plan to have things configured.

Musicman

Well I upgraded the modem to the X8. Got it home and setup, placed it in bridge mode. 

Same exact issue.

1.Plug orbi into the X8 2.5 gig port orbi app gets 1441 down and 250 up

Anything plugged into the Orbi ethernet ports goes initially to 900 and then tapers to 150. Upload is fine at 250

2.Plug orbi into the X8 1 gig port orbi app gets 964 down and 250 up

Anything plugged into the Orbi ethernet ports goes to 945 up and 250 down

3. Wifi speeds are a sustained 650-800 either way.

Makes you wonder what the problem is - my XB7 and 960 do not have this issue.  Seems more commonly reported with the XB8, but I wonder if later versions of the XB7 have it and whatever "that" is has carried over into the XB8.  Our XB7 is probably two years old.  If that's the case, it may be a hardware compatibility problem in that I'd assume our XB7s are running the same firmware.  Mine says:

I do hope it gets sorted because certainly at some point we'll probably get pushed toward an XB8 or whatever comes next.

bullm00n my firmware is the exact same as yours except it is CGM4981COM_6.7p14s1_PROD_sey.  

gregnauman wifi speeds on the RBR850 weren't impacted when using the 2.5GB port on the XB8, but WiFi over satellites was a little slower when using the XB8 2.5mGig port likely due to the reduced LAN speeds (closer to 500Mbps instead of 700Mbps).  My satellites are connected with ethernet backhaul, so that may be why.  Since the same behavior happens on my 2.5GB switch I'm thinking this is xfinity's issue.  I also saw a similar thread posted on the eero reddit about reduced speeds with the XB8 despite the network being connected over ethernet.