RBR750 download speed drops a lot and below upload speed some of the time

[Hsri07]

I installed the AX 4200 RBR750 router + 1 satellite a couple of months ago and it worked well - consistently 200Mbps+ download, 32Mbps+ upload everytime I checked (at different times of the day or at night). Internet is via cable model using Optimum. A few days ago I got a message to update the firmware and I updated it to V3.2.16.6_1.4.4 - 1. All of a sudden, past few days I started observing weird results some of the times - download speed drops to as low as 7Mbps to 20Mbps while upload consistently shows 32Mbps+. I have hard booted the cable modem & router/satellite multiple times and even swapped out the old cable modem with a new one 2 days ago. Today 8/22 I did a factory reset of the router & satellite using orbilogin.com and did hard reboots of the cable modem and wireless routers & satellites to reset everything. At around 12pm when I finished with that, all devices shows 200Mbps+ download speed at 32Mbps+ upload speed on 5 different devices, so I figured that had fixed everything. But, when I tested everything again at around 4:30pm EST, same as before - download speed has plunged to 7Mbps to 14Mbps while upload continues to be 32Mbps+ - tested on smartphone, iPad, PC. Orbilogin admin also shows 14Mbps download speed and 31Mbps upload speed. So, clearly the problem is NOT FIXED. Absolutely nothing has changed between noon today and 4:30pm today - why is download speed plunging within 4 hours of doing just fine?  Is it an Orbi Ax 4200 (RBR750) problem or is the problem with the cable modem (I have an Optimum technician coming home to check but he won't be able to help if this is an Orbi problem). Any suggestions/troubleshooting ideas? How do I isolate the problem if it is indeed cable Internet?

[Hsri07 · Accepted solution]

It was Optimum cable that had the problem. The technician came, fixed something in the cable box on the street and it is fine so far! Thanks for the responses and apologies for the time.

[FURRYe38]

What is the Mfr and model# of the Internet Service Providers modem/ONT the NG router is connected too?

What is the size of your home? Sq Ft?
What is the distance between the router and satellite(s)? 30 feet is recommended in between RBR and RBS to begin with depending upon building materials when wirelessly connected. https://kb.netgear.com/000036466/How-far-should-I-place-my-Orbi-satellite-from-my-Orbi-router

What channels are you using? Auto? Try setting manual channel 1, 6 or 11 on 2.4Ghz and any unused channel on 5Ghz.
Any Wifi Neighbors near by? If so, how many?

Try disabling the following and see:
Armor, IPv6 and Set 20/40Mhz Coexistence to 40Mhz only. Set Short preamble instead of Long preamble modes. Save settings and reboot the router and satellite(s).

What are your wired speeds with a PC? 

What FW updated thru the Orbi app or RBR web page? 

What version of FW did you have loaded prior? 

[Hsri07]

Cable Modem is Arris TM1602 - swapped in a new one 2 days ago (yes, I can get a new cable modem myself and use it but would like to resolve this issue first and then consider getting my own modem).

Re: other questions - two things to note - first, it worked perfectly fine in the same home, same place where the router & satellite were setup earlier, nothing has changed. We have no wifi interference and no additional electronic devices in the past few months. Secondly, it worked perfectly at 12pm EST but is dropping speed at 4:30p EST same day. 

No Armor. I will try the other changes you suggest below but I am still confused as to what can cause something to change between noon and 4:30pm same day after I have done a factory reset, hard booted everything and it all seemed to work fine? Does the fact that it remains 
"On" for a few hours cause a decay in performance? And it all worked well for 2 months, has this firmware update caused problems? Or the storm has cuased problems with the cable modem and cable internet?

Going to hardwire ethernet to my laptop to the cable modem to test that and also hardwire ethernet to the RBR750 to test that too.....

[FURRYe38]

You might revert back FW versions. Something maybe different on the 7 series vs 8 series Orbi. 

I would make contact with NG support about this as well. 

[Hsri07]

More weird results, after download speed plunged at 4:30pm EST, we stepped out and when we returned home around 8pm, speed was back up to 198Mbps download!! Upload stays good all the time, it is always the download speed that plunges.

And today morning (8/23), speed has plunged back down to 4Mbps!

All this time since 12pm yesterday 8/22, absolutely nothing has changed and I have tested on 4 devices, so it is not a device problem.

To repeat:

- RBR750 with 1 router and 1 satellite working fine for approx 2 months. Firmware was updated 4 days ago. I am noticing very erratic performance in download speeds only, upload is always fine. have hard booted cable modem and router/satellite multiple times. 8/22 morning, factory reset router & satellite and it seemed that it was working properly (download speed 200Mbps), 4:30pm speed dropped to around 10Mbps, 8pm back to 198Mbps, 8/23 morning back down to 4Mbps. No changes anywhere during all this time!

Going to test laptop with ethernet to cable modem and then to router to see if I can isolate the problem. 

[FURRYe38]

And a factory reset and setup from scratch was performed on the RBR after the update? 

Was your system updated automatically, via orbi app or did you manually apply the FW update files yourself? 

[Hsri07]

I did a factory reset (atomatic update from orbilogin.com) after the firmware update. Once the factory reset was completed, I did a firmware update availab;e check and it said no new firmware update i.e. the last update remained after the factory reset. Going to check internet via ethernet cable and laptop shortly.

[Hsri07]

needed an usb to ethernet adapter to connect my laptop to the cable modem (laptop has no ethernet ports!). bought that today and hard wired to the cable modem and bingo, problem is with the cable internet! Download speed 15Mbps, upload 32Mbps.

Hearing that the storm has caused havoc on both Fios and Optimum.....this confirms that. At least for now, the problem doesn't seem to be related to RBR750.

My apologies for wasting people's time......will update this thread once optimum fixes this and I am able to ensure that RBR750 works fine.

[FURRYe38]

Good to hear the issue is with ISP. Let us know how it goes. Keep on them. 

https://community.netgear.com/t5/Orbi-AX/RBK-852-New-Firmware-Version-V3-2-16-6-1-4-4/m-p/1962430/hi...

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@Hsri07 wrote:

needed an usb to ethernet adapter to connect my laptop to the cable modem (laptop has no ethernet ports!). bought that today and hard wired to the cable modem and bingo, problem is with the cable internet! Download speed 15Mbps, upload 32Mbps.

Hearing that the storm has caused havoc on both Fios and Optimum.....this confirms that. At least for now, the problem doesn't seem to be related to RBR750.

My apologies for wasting people's time......will update this thread once optimum fixes this and I am able to ensure that RBR750 works fine.

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[Hsri07 · Accepted solution]

It was Optimum cable that had the problem. The technician came, fixed something in the cable box on the street and it is fine so far! Thanks for the responses and apologies for the time.

[FURRYe38]

Good to hear it's fixed. Please mark your thread as solved so others will know. 

Enjoy.