Will a new modem increase my network speed?

[Mike-48]

Comcast 1.2 Gb service > Netgear CM1150V cable modem > ASUS RT-AX86U router with Merlin firmware

We signed up for 1 Gb service and I bought the Netgear modem about 14 months ago. It was the fastest Comcast voice modem available. I remember testing speed and getting 800-900 Mbps, which I thought was pretty good.

Now, Comcast has increased our service speed to 1.2 Gbps, they list the CM1150V as "incompatible," and download speed tests at about 450-550 Mbps. I don't test regularly, so I don't know know when that started. Comcast was here today, tested everything & said it was fine, but that "some computers just can't handle the high speeds." I think the guy was competent with the testing (he's not the first), but the last statement seems questionable.

One opinion is that with the speed increase, the modem is now using a Comcast configuration file for lower speeds, and to get the full speed I would need a modem like the Netgear CM2050V, top rating 2.5 Gb.

I don't mind spending the money, but worst case would be to install the CM2050V and find no change in speed.

Advice, please!

[Edited to fix router model #]

 

[Tech9]

No matter what speed the modem is capable of, the best you can get with RT-AX68U is about 940Mbps, limited by the WAN port. I don't know what modem is compatible with your new ISP service. You have to ask the ISP. Still, up to 940Mbps to your router.

 

[Mike-48]

Sorry -- my typo. It's an RT-AX86U, which has a 2.5 Gb port. I've edited the original post to fix that.

Comcast says the CM-2050V is compatible. But they also say the current modem is rated to 948 Mbps. Something is throttling the current speed -- but is it Comcast? the modem? or the router?

 

[dosborne]

Connect directly to your Netgear modem and run a speed test for comparison.

 

[Mike-48]

Connect directly to your Netgear modem and run a speed test for comparison.

Good suggestion - thanks. Laptop direct to modem: 591 Mbps. Laptop through router: 420-540 Mbps.

I was nervous without firewall and NAT and didn't think to take >1 speed test with direct connection. Still, that's the highest download speed I've seen lately.

Through the router, with nothing else plugged into it and WiFi off, the range is 420-540 Mbps.

Turning off AI Protection gives 530-545 Mbps. So that seems to have a hit, maybe 50 Mbps.

 

[L&LD]

If you don't mind spending the money, and you want to use as much of your paid for ISP speeds, get the new modem.

 

[Mike-48]

I don't mind spending the money if it doesn't become obsolescent in a year, like the previous one. That's what torqued me, buying a new modem for the service and having Comcast declare it "incompatible" soon thereafter. I like to get at least 3 years out of this stuff.

 

[L&LD]

I would ask kindly that they replace the modem with one that works then (and at no charge), for the speeds you're paying.

Are they the only ISP provider in your area?

 

[Mike-48]

Are they the only ISP provider in your area?

There's also CenturyLink, but I've never met a soul who is happy with them. Comcast is quite reliable, if expensive.

 

[Mike-48]

Just for the record, I swapped in the CM2050V, and that gave no increase in speed. I am in contact with Comcast Tech Support on their own forum, so I won't belabor the topic here -- but I will post any resolution. I'm not discouraging possibly helpful comments here, but I did want the helpful SNB folks to know that I'm getting help (I hope it's help ) directly from Comcast.

 

[L&LD]

I had a feeling that this is on the ISP. Keep at them, ask them to upgrade you (at no charge) for your troubles, to the modem that finally gets you the speeds you're paying for.

 

[sfx2000]

No matter what speed the modem is capable of, the best you can get with RT-AX68U is about 940Mbps, limited by the WAN port.

That is not bad, it's what one would expect over gigabit ethernet - heck, on the LAN side, that is about the max one would get, not having to do NAT, routing, etc...

 

[Tech9]

That is not bad

Yes, but only under specific conditions. It needs NAT acceleration tricks to reach Gigabit, like all home routers. Any firmware option incompatible with NAT acceleration drops the throughput to about 350Mbps. This is what Asus and other manufacturers always forget to mention in specifications.

 

[avtella]

200-300 Mbps I think was more like an R7000 or AC68U with the old 1 GHz Cortex A9 CPUs. The R7800 could hit around ~700 Mbps in OpenWRT if I recall correctly and newer Netgear / Asus models I would assume may also pull off 600-700 Mbps+ without NAT acceleration

 

[Tech9]

Asus models I would assume may also pull off 600-700 Mbps+ without NAT acceleration

Tested already. Broadcom ARMv8 1.8GHz cores can't reach 400Mbps. Qualcomm SoC in R7800 has NSS hardware, it's different.

 

[Mike-48]

A few points:

1. Connecting my laptop directly to the cable modem gave a only a slight increase -- about 590 Mbps, instead of the 450-550 I get through the modem with AI Protection on. So I am saying, it's not a router limitation. The direct connection was ONE test only. I get too nervous to leave my laptop hooked up that way for long.
2. I am pretty sure that when they first installed the service, I was getting about 850 Mbps through my old modem (CM1150V) and router (RT-AC88U). I'm getting around half of that now.

3. No matter what speed the modem is capable of, the best you can get with RT-AX68U is about 940Mbps, limited by the WAN port. I don't know what modem is compatible with your new ISP service. You have to ask the ISP. Still, up to 940Mbps to your router.

   I repeat, since the comment by @Tech9 seems to be taking on a life of its own: that was my typo; it's an RT-AX86U with a 2.5 Gb port. And really, if I could get 940 Mbps out of the modem, I would stop bugging Comcast.
4. They are selling this as 1.2 Gbps service, and all my equipment meets their specifications. They are providing half that speed at best. My complaint is that simple.

Interestingly, no one Comcast has sent has had equipment to test the speed I'm getting. The last tech used his iPhone on WiFi. What they have confirmed is that the signal strength is OK and that the right number of channels are bonding.

Tech Support has had me power-cycle the modem more times than I can count; they have reset it; checked the MAC; and re-provisioned it, all with no effect other than wasting hours of my time. At this point, my guess is that the infrastructure on my street needs to be upgraded.

 

[avtella]

Tested already. Broadcom ARMv8 1.8GHz cores can't reach 400Mbps. Qualcomm SoC in R7800 has NSS hardware, it's different.

The dual NSS offload cores were’t functional in OpenWRT, I think somone is still working on getting them working. Those tests were purely using the main 1.7 GHz Cortex A15 cores without NAT acceleration. Of corse using SQM Piece of cake or any other QoS would really start sapping WAN throughput further unlike stock where QoS was offloaded to the NSS cores.

As for the main topic, OP Comcast’s 1.2 is actually 1.4 Gbps down as they overprovision. So yeah you’re getting a lot less than you should. Your current modem should hit 900+ Mbps. My guess is it’s infrastructure as you suspect. You could get a modem from a store temporarily like an SB8200 or one from a friend just to confirm. Lastly if you have multiple coax connections through the house if there is an issue with the splitting it can cause issues as well, at my home Comcast removed connections to what I assume was a faulty splitter in our attic a few years ago and things improved drastically.

 

[RMinNJ]

"..Connecting my laptop directly to the cable modem gave a only a slight increase -- about 590 Mbps, instead of the 450-550...

What kind of laptop do you have? I found I needed a rather fast i7 and intel nic connected right to the modem.. My older i3 and ?? Nic was not able to do gigabit...maybe 650. If you have a very fast laptop I would think you should get much higher connected right to the modem else comcast is not provisioning you correctly.

Definitely check that you are using a good Cat6A cable to the modem. I had a Cat 5e cable that was good on 200mbit and when my service went to 300 my router did not I till switched the cable. When I went to 1G service (im not Comcast) I found my laptop problem and I found one of my switches would not really do gigabit (limit was like 500-600).

After that with a new 2.5 modem and if the Asus can use its 2.5 as a WAN port maybe you can break over 940. But seems a bit much for the extra few Mbits... the modem you have should be plenty.

 

[Mike-48]

My guess is it’s infrastructure as you suspect. You could get a modem from a store temporarily like an SB8200 or one from a friend just to confirm. Lastly if you have multiple coax connections through the house if there is an issue with the splitting it can cause issues as well, at my home

Glad to report, the Comcast tech agreed that infrastructure should be checked at this point, and they are sending someone to do that. As to coax, the last Comcast on-site person replaced the splitter and disconnected an unused coax connection, so that's all been cleaned up.

Oh, and since I already have installed the faster cable modem, I think I'll keep it in place. An extravagance, but I'm saving a lot these last two years on eating out.

What kind of laptop do you have? I found I needed a rather fast i7 and intel nic connected right to the modem..

It's a recent Acer with a fast i7 and a 1Gb NIC card. Yes, the modem>router cable is Cat 6, and it was a Cat 6 cable when I was testing.

 

[Mike-48]

Now I am puzzled again. I just now noticed that the router has its own speed test, which indicates >1000Mbps. Have I been wrong all this time, and been on the phone with Comcast for nothing?

Yet I've never been able to get more than about half that out of the router, even with QoS and AIProtection turned off. What the heck have I been missing? Maybe my laptop's NIC or the house wiring are the bottlenecks? My face is red . . . I think.