download and upload speeds dropped for no reason

As of the past 5 days, my download and upload speeds seem to have dropped for seemingly no reason. I have spoken with a Spectrum support representative who told me everything is fine on their end and I should be getting 60 Mbps download. Instead, I get variable rates of speed each time I test that vary between 16.9 Mbps to 38.5 Mbps (download), The numbers are always random each time I test. I have secured, unplugged and rebooted the modem and router multiple times with no difference. The modem is a Netgear cm400 and router is a Cisco Linksys WRT54G2 V1. There are no splitters in my apartment. Any help would be appreciated.

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

<tabindex=-1>Startup Procedure
Acquire Downstream Channel387000000 HzLocked
Connectivity StateOkOperational
Boot State----
Configuration File----
IP Provisioning ModeIPv6 Onlyipv6Only(1)

Downstream Bonded Channels
ChannelLock StatusModulationChannel IDFrequencyPowerSNRCorrectablesUnCorrectables
1LockedQAM 2561279000000 Hz3.7 dBmV39.8 dB183801
2LockedQAM 2562285000000 Hz3.6 dBmV40.3 dB11501633
3LockedQAM 2563291000000 Hz3.9 dBmV40.3 dB23654
4LockedQAM 2564297000000 Hz3.3 dBmV40.3 dB229131621
5LockedQAM 25617375000000 Hz1.0 dBmV39.8 dB2339511
6LockedQAM 25618381000000 Hz0.4 dBmV39.3 dB14971416
7LockedQAM 25619387000000 Hz1.3 dBmV39.8 dB42431958
8LockedQAM 25620393000000 Hz1.3 dBmV39.8 dB85861450

Upstream Bonded Channels
ChannelLock StatusUS Channel TypeChannel IDSymbol RateFrequencyPower
1LockedATDMA25120 Ksym/sec24200000 Hz45.8 dBmV
2LockedATDMA35120 Ksym/sec30600000 Hz45.8 dBmV
3Not LockedN/AUnknown0 Ksym/sec0 Hz45.8 dBmV
4Not LockedN/AUnknown0 Ksym/sec0 Hz45.8 dBmV

Current System Time: Thu Apr 26 06:24:35 2018
Lead Moderator

Re: download and upload speeds dropped for no reason

Good morning!


There is a list of additional information that would be helpful for your peers to help diagnose the the issue:




Julia R.
Spectrum-Social Media Customer Care
Lead Moderator-Community Forums

Trusted Helper

Re: download and upload speeds dropped for no reason



You need a Docsis 3.0 modem or higher for the faster speeds.  If you have Wireless Internet, a Series N router or better for good dynamic signal range.  If the problem persists, contact Spectrum for a signal and drop line test.  Additionally, there may be something further down the street, such as a corroded line or a bad tap causing the drop in signal.


When you set up your service call, avoid resetting anyy boxes, modems, or routers for at least six hours, as the tech needs to see the error codes on the signals, and equipment resets will reset the error codes to zero that the tech needs to see.  Get a tech out to check your signals.  If the problem is worse at a certain time of the day or night, make sure to let the tech know that as well.




Re: download and upload speeds dropped for no reason

The CM400 is a DOCSIS 3.0 modem. The fact that you're only getting 2 upstream channels when you should have 4 along with the fluctuations in power levels on the downstream channels seems to indicate a physical coax issue. It could be loose or corroded connections anywhere from the modem to your drop, to the street, or even further back.


If all your connections are tight and there are no unnecessary splitters, I agree with Satch that you need to get a tech out to inspect everything.


Re: download and upload speeds dropped for no reason

FYI ... apartments are notorious for having jacked up wiring.

Proven Sharer

Re: download and upload speeds dropped for no reason

Your connection speed appears to be limited because you are testing over WiFi using a router that is limited to no more than 54 Mbps, and usually operates at 22 to 42 Mbps.  

You also have signal impairments that further reduce your maximum speed.  Your modem shoud be showing a total of four return (US) channels, but the signal level report only shows two of them working.  The best chance for immediate improvement is to have Spectrum re-flash your modem for 60 Mbps service.   That step should restore the two missing Upstream Bonded channels and get your connected DL speed back up to between 48 and 73 Mbps.   FYI, the highest download speed that the Netgear CM400 cable modem would ever see on Spectrum's network is 100 Mbps. 


 Below is a rather ancient review posted on the c-net.com web site in the summer of 2009, which gives a clue how far out of date your legacy router really is:


Alternatives to the WRT54G2


The WRT54G2 is the new design of the old legacy WRT54G router. This is a Wireless-G (802.11g) router that offers slow wireless speeds and caps at 54Mbps.  As most wireless routers nowadays support the newer and much faster 802.11n (that caps at 300Mbps or more), the only reason you would want to buy the WRT54G2 is its price.  You can find one online for less than $50.

As far as performance is concerned, the router will offer short range (around 50 feet) and limited throughput speed.  If you just need to share Internet and casual home networking, the WRT54G2 will deliver.  For heavy Internet usage and online gaming, it's generally a better idea to get a Wireless-N router.   For Linksys Wireless-N routers that have similar design and setup software as the WRT54G2, check this list of reviewed Linksys routersThe best Wireless-N alternative to the WRT54G2, based on price, however, is the WRT160N.  It costs about the same but offers much faster speed and much longer range. 

Again, this article was published some nine years ago.  Many of the routers on the included list have already been made obsolete by newer technologies like AC1900 WiFi and multiple beam forming antennas.



Re: download and upload speeds dropped for no reason

All of my connections ( desktop pc and a PS4 system) are wired with a lan cable. Nothing is currently wireless. I had the tech support guy reflash the modem as well which didn't appear to change anything. The service cable leading into the apartment originates from a utility poll. It may also be the old router dying I suppose. Will be looking into getting a new one and see if the situation improves.  Thank you all for the replies so far.

Proven Sharer

Re: download and upload speeds dropped for no reason

If you are planning to buy a new router, be SURE it has both Gigabit ethernet ports AND uses AC1900 wireless protocol.  Also remember that unless the router's WiFi uses MULTIPLE beam-forming antennas, the slowest device on WiFi will limit the speeds available to all of them.