Nighthawk X4S Slow Download Speeds

[DaveMoreland]

My X4S AC3200 cable modem occasionally will have the download speeds slow to 1 mbps or less while the uploads remain normal at 35-40 mbps.  I am paying for 400 mbps download speeds.  You can restore factory settings on the modem and it will fix the problem but it will occur again at random times.  Usually stays fixed for a couple of months or more before you have to restore the factory settings again.  Anyone else having this problem?  

[FURRYe38 · Accepted solution]

Ok hoping you or ISP and get it working better...

[FURRYe38]

What model series modem do you have? AC3200 is a combined wireless speed, not a modem model.

[DaveMoreland]

It's a C7800v2

[FURRYe38]

Be sure your using a good quality LAN cable between the modem and PC. CAT6 is recommended. 

What is the connection rate seen on the PCs ethernet adapter. Should see 1000Mpbs

Please post a copy and paste of the modems connection status page.

Have the ISP check the signal and line quality UP to the modem. Be sure the ISP provisions the modem correctly.
Be sure there are no coax cable line splitters in the between the modem and ISP service box. 
Be sure your using good quality RG6 coax cable up to the modem. 
Be sure to power OFF the modem for 1 minute then back ON.
https://community.netgear.com/t5/Cable-Modems-Routers/General-info-and-Troubleshooting-for-Cable-Mod...
https://kb.netgear.com/24311/Power-level-guidelines-for-a-NETGEAR-cable-modem-router?article=2431

[DaveMoreland]

1. Yes, we are using CAT6.

2. Connection rate is 1000 Mbps

3. 

Apply             Cancel

Frequency start Value

This field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect.

Starting Frequency

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<tabindex=-1>Startup Procedure</tabindex=-1>

Procedure	Status	Comment
Acquire Downstream Channel	561000000 Hz	Locked
Connectivity State	OK	Operational
Boot State	OK	Operational
Security	ENABLED	BPI+
IP Provisioning Mode	Honor MDD	APM

---

<tabindex=-1>Downstream Bonded Channels</tabindex=-1>

Channel	Lock Status	Modulation	Channel ID	Frequency	Power	SNR	Correctables	Uncorrectabables
1	Locked	QAM256	1	561000000 Hz	-9.3 dBmV	35.9 dB	1	0
2	Locked	QAM256	2	567000000 Hz	-9.8 dBmV	35.7 dB	2	0
3	Locked	QAM256	3	573000000 Hz	-9.4 dBmV	36.0 dB	6	0
4	Locked	QAM256	4	579000000 Hz	-10.3 dBmV	35.5 dB	10	0
5	Locked	QAM256	5	585000000 Hz	-10.1 dBmV	35.6 dB	5	0
6	Locked	QAM256	6	591000000 Hz	-10.4 dBmV	35.7 dB	5	0
7	Locked	QAM256	7	597000000 Hz	-10.6 dBmV	35.5 dB	7	0
8	Locked	QAM256	8	603000000 Hz	-10.8 dBmV	35.2 dB	18	0
9	Locked	QAM256	9	609000000 Hz	-10.9 dBmV	35.3 dB	5	0
10	Locked	QAM256	10	615000000 Hz	-11.3 dBmV	35.0 dB	4	0
11	Locked	QAM256	11	621000000 Hz	-12.1 dBmV	34.7 dB	13	0
12	Locked	QAM256	12	627000000 Hz	-12.8 dBmV	34.5 dB	16	0
13	Locked	QAM256	13	633000000 Hz	-12.4 dBmV	34.7 dB	16	0
14	Locked	QAM256	14	639000000 Hz	-11.9 dBmV	34.8 dB	20	0
15	Locked	QAM256	15	645000000 Hz	-11.0 dBmV	35.1 dB	5	0
16	Locked	QAM256	16	651000000 Hz	-11.0 dBmV	35.0 dB	7	0
17	Locked	QAM256	17	657000000 Hz	-10.7 dBmV	35.1 dB	5	0
18	Locked	QAM256	18	663000000 Hz	-10.6 dBmV	35.2 dB	5	0
19	Locked	QAM256	19	669000000 Hz	-10.2 dBmV	35.2 dB	7	0
20	Locked	QAM256	20	675000000 Hz	-10.9 dBmV	35.0 dB	3	0
21	Locked	QAM256	21	681000000 Hz	-10.0 dBmV	35.3 dB	3	0
22	Locked	QAM256	22	687000000 Hz	-10.7 dBmV	35.2 dB	6	0
23	Locked	QAM256	23	693000000 Hz	-10.1 dBmV	35.3 dB	4	0
24	Locked	QAM256	24	699000000 Hz	-10.5 dBmV	35.3 dB	2	0
25	Locked	QAM256	25	705000000 Hz	-9.7 dBmV	35.3 dB	21697	62905
26	Locked	QAM256	26	711000000 Hz	-10.2 dBmV	35.2 dB	26128	67909
27	Locked	QAM256	27	717000000 Hz	-9.4 dBmV	35.4 dB	1	0
28	Locked	QAM256	28	723000000 Hz	-10.2 dBmV	35.1 dB	3	0
29	Locked	QAM256	29	729000000 Hz	-9.7 dBmV	35.2 dB	2	0
30	Locked	QAM256	30	735000000 Hz	-10.1 dBmV	35.2 dB	1	0
31	Locked	QAM256	31	741000000 Hz	-9.5 dBmV	35.2 dB	0	0
32	Not Locked	Unknown	0	0 Hz	0.0 dBmV	0.0 dB	0	0

---

<tabindex=-1>Upstream Bonded Channels</tabindex=-1>

Channel	Lock Status	US Channel Type	Channel ID	Symbol Rate	Frequency	Power
1	Locked	ATDMA	19	2560 Ksym/sec	25000000 Hz	50.5 dBmV
2	Locked	ATDMA	17	5120 Ksym/sec	37500000 Hz	50.8 dBmV
3	Locked	ATDMA	18	5120 Ksym/sec	30700000 Hz	50.8 dBmV
4	Locked	ATDMA	20	2560 Ksym/sec	21400000 Hz	50.0 dBmV
5	Not Locked	Unknown	0	0 Ksym/sec	0 Hz	0 dBmV
6	Not Locked	Unknown	0	0 Ksym/sec	0 Hz	0 dBmV
7	Not Locked	Unknown	0	0 Ksym/sec	0 Hz	0 dBmV
8	Not Locked	Unknown	0	0 Ksym/sec	0 Hz	0 dBmV

---

<tabindex=-1>Downstream OFDM Channels</tabindex=-1>

Channel	Channel ID	Indicator	Subcarrier Zero Frequency	Active Subcarrier Number Range	Total Codewords	Uncorrectable Codewords
1	33	Primary	677600000 Hz	1588 ~ 2507	249864617	0
2	0	Other	0 Hz	0 ~ 0	0	0

---

<tabindex=-1>Upstream OFDMA Channels</tabindex=-1>

Channel	UpstreamIsMuted	Ranging Status	Subcarrier Zero Frequency	Active Subcarrier Number Range	Symbols Per Frame	Tx Power
1		Other	0 Hz	0 ~ 0	0	0 dBmV
2		Other	0 Hz	0 ~ 0	0	0 dBmV

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Current System Time: Tue, Aug 16, 2022 12:14:20

4.ISP has been out and has replaced coax beginning at the pole outside all the way into the house. (We had the inside coax replaced)

5. Signal quality has been checked and ISP provisioned modem correctly.

6. No splitters between modem and ISP service box. 

7. All interior coax was replaced and new coax professionally installed.

8.  Power off procedure has been followed. 

[FURRYe38]

You power levels are too LOW:

https://kb.netgear.com/24311/Power-level-guidelines-for-a-NETGEAR-cable-modem-router?article=2431

Also you have correct and un-correctables that should be zeros.

Check your coax fittings and ensure they are snug. 

Have the ISP check for this and the power levels. The ISP will need to work with you on this. 

Be sure to use Ooklas installable speed test app to test speeds with a wired PC. Ensure other devices are disconnected or not using bandwidth before testing. 

[DaveMoreland]

Thank you for this info!  We have Suddenlink so good luck with their customer service.  

I'll do some troubleshooting...does low power level generally indicate signal loss at a splitter or cable connection?

I'll check and make sure there's not a splitter somewhere in the attic that I'm missing.

Excuse my ignorance but what would cause the "correct and un-correctables" issues and what should I be looking for to correct that.

And another stupid question.  Does a signal amplifier that would be used on a tv antenna signal help boost a cable internet signal and would there be any advantage to installing an amplifier in this case? Or would that even be possible?🤔

I do use Ookla Speedtest on a wired PC.  When it has an issue the download speeds are 1mbps or less and the uploads are in the 40 mbps range.  When things are working I generally get anywhere between 90 and 250 mbps downloads with the uploads staying about the same.  This speed is restored when we restore the factory settings on the router.  

Thanks again for all your help!

Dave

[FURRYe38]

Yes can be due to a splitter or cable connection. 

Loose cable jacks or not screwed in all the way, kinked cabling or bad cabling or splitters can cause correct and un-correctables. The modems is trying to correct data flow where i can and can not. This is where this gets reported. 

I would ask the ISP first if a amp maybe needed or should be used. Not sure what kind of amp that could be used if one is needed. 

[DaveMoreland]

Thanks for the great advise!  I will check for coax connection issues.  

This is an essential connection since this is a computer that is used for a work at home job.  We are presently paying for a second internet provider (T-Mobile 5G) just because this one has so many issues! Unfortunately T-Mobile is not perfect either so at this time it makes sense to keep both. 

[FURRYe38 · Accepted solution]

Ok hoping you or ISP and get it working better...

[FURRYe38]

And if ISP doesn't do anything, you could short term rent one of there modems to see if the problem continues, if so, this can be additional help in proving the ISP needs to fix this. 

[DaveMoreland]

Good idea. I used to have one of their modems but it got zapped in an electrical storm which prompted me to buy my own.

I never had this problem with the cable modem from Suddenlink so that's why I think there's some issue with this particular model of modem. 

[FURRYe38]

👍

Also I would place a laptop cooler under this modem as well. Helps keep the unit cooler and helps with electronics longevity as well. 

[DaveMoreland]

Thanks!  I will look into that.

[FURRYe38]

I use one of these:

https://www.amazon.com/Thermaltake-Massive-Adjustable-Notebook-CL-N004-PL20BL/dp/B00IGSATZY/ref=sr_1...

[DaveMoreland]

Thanks again for all  your help!

[FURRYe38]

👍