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R7500 slow LAN speeds with Arris 6190 cable internet modem

tslo
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R7500 slow LAN speeds with Arris 6190 cable internet modem

I activated a new cable internet modem today and my LAN throughput, as measured via speedtest.net, dropped significantly

 

Internet Provider: Comcast, Tier: Performance Pro

Setup: Arris SB6190 -- R7500v2 -- wired PC

 

Up until noon today, i was running an older Motorola SB6120 cable internet modem (DOCSIS 3.0 4x4 channels).  I bought this right when Comcast upgraded to DOCSIS 3.0 to enjoy the benefits.  The 6120 is getting old and I wanted to upgrade to a newer modem and bought the Arris SB6190... trying to future-proof myself, at least for the *near* future in the DOCSIS 3.0 context.

 

Speeds (via speedtest.net):

 

SB6120 (4 down/4 upstream channels):

--Router (via the QoS config page/speedtest.net):  ~90Mbps down/~6Mbps up

--PC: ~80 down/6up

 

SB6190 (16 down/4 up-- 6190 supports 32, but only 16 bonded for my service):

--Router: ~90Mbps/6Mbps

--PC:~21Mbps/6Mbps

 

Details:

--R7500v2 firmware 1.0.3.4

--QoS = Off

--Traffic monitoring = Off

--Guest Network = Disabled

--NIC on the PC is set to auto-negotiate 10/100.  It's a integrated NIC on my HP PC, NVIDIA nForce 10/100

 

I got a case, called support, went through the following:

--Changed 2.4 wireless channels to 11, then 9 (I just did what they asked... how this impacts LAN traffic, I don't know)

--Changed MTU size to 1432

--Reset to factory settings

 

None of the following resolved the issue; still only getting ~21Mbps at the PC when the Router is used.

 

However, if I bypass the R7500, plugging the PC into the SB6190, then i'm back to ~90/6Mbps down/up speeds.

 

I've seen other similar reports (via some internet searches) but no real solutions.

 

Anyone resolve a similar issue?

 

Thanks!

Model: R7500v2|Nighthawk X4 AC2350 Smart WiFi
Message 1 of 5

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tslo
Aspirant

Re: R7500 slow LAN speeds with Arris 6190 cable internet modem


@JamesGL wrote:

 

I think you may need to replace the new modem. It shows that the router is working when using the old modem. Changes has been made when using the new modem but still the same.

 


 

Hi James,

 

Thanks for the reply.

 

The test also shows that the modem works fine without the router; wired connection is fine. 

 

So, Arris says it's the modem ("we're just a pass through"); Netgear says it's the router.

 

Also, WiFi throughput was fine.  The issue was specific to LAN throughput.

 

So, to me, this indicates some issue with the router/modem communication. 

 

Hard to tell which is the culprit, but the fact remains that the only thing that changed was the modem.

 

My resolution: switch the hardware back to the SB6120, return the 6190 and use that setup until it dies or is obselete (or not able to provide the speeds available with the Xfinity internet tier that I've purchased).

 

Thanks... 

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tslo
Aspirant

Re: R7500 slow LAN speeds with Arris 6190 cable internet modem

I switched back to the older Motorola SB6120 modem tonight and had Comcast reactivate it.

 

Immediately went back to speedtest.net reported speeds, at my Windows PC, of 81.24Mbps down/6.08Mbps up, through the router-- no other changes.

 

Although I'm not using QoS, I have used the embeded speedtest in the admin console to report some speed metrics at the router.  That speedtest really doesn't show that much of a decrease in overall speed with the old modem, 89.36/6.10 (SB6190) vs 89.72/6.69 (SB6120).

 

Although I'd really like to figure it out, at this point I'm going to return the modem in a couple of days if I can't, given no real performance difference for internet service tier that I have.  The R7500's wireless signal is really good for my old lathe/plaster house, so it's worth keeping my current setup.

 

Would still be open to any suggestions, as I really would like to know why this is happening.  Thanks

 

 

 

 

Message 2 of 5
JamesGL
Master

Re: R7500 slow LAN speeds with Arris 6190 cable internet modem

Hi tslo,

 

I think you may need to replace the new modem. It shows that the router is working when using the old modem. Changes has been made when using the new modem but still the same.

 

JamesGL

Community Team

Message 3 of 5
JamesGL
Master

Re: R7500 slow LAN speeds with Arris 6190 cable internet modem

Hi tslo,

 

We’d greatly appreciate hearing your feedback letting us know if you need further assistance.

 

JamesGL

Community Team

Message 4 of 5
tslo
Aspirant

Re: R7500 slow LAN speeds with Arris 6190 cable internet modem


@JamesGL wrote:

 

I think you may need to replace the new modem. It shows that the router is working when using the old modem. Changes has been made when using the new modem but still the same.

 


 

Hi James,

 

Thanks for the reply.

 

The test also shows that the modem works fine without the router; wired connection is fine. 

 

So, Arris says it's the modem ("we're just a pass through"); Netgear says it's the router.

 

Also, WiFi throughput was fine.  The issue was specific to LAN throughput.

 

So, to me, this indicates some issue with the router/modem communication. 

 

Hard to tell which is the culprit, but the fact remains that the only thing that changed was the modem.

 

My resolution: switch the hardware back to the SB6120, return the 6190 and use that setup until it dies or is obselete (or not able to provide the speeds available with the Xfinity internet tier that I've purchased).

 

Thanks... 

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