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Slow download speed
Hi, all,
My Comcast cable internet has been only running at less than one third of the 75Mbps advertised download speed. When I use Zoom chat to work remotely, the incoming audio/video is really bad. Attached is a screenshot of the cable connection page of my Netgear CM400 cable modem. Is there any problem with the cable signal? Your help is much appreciated.
So the uncorrectables are a bit high. If you have any splitters, attenuators, amplifiers in line, remove them. If you still get that many errors, the isp needs to check the line.
And you know your speeds from the cm400 is at least 80mbps download.
Do you have a different device you can test with?
5 Replies
Sorry, the attached image might be hard to view. Here is the table I copy-n-pasted. Are the power levels normal? Are the error rates OK?
Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables UnCorrectables 1 Locked QAM 256 4 423000000 Hz 8.0 dBmV 36.8 dB 1398 9992 2 Locked QAM 256 5 429000000 Hz 8.4 dBmV 37.3 dB 1796 9494 3 Locked QAM 256 6 435000000 Hz 8.3 dBmV 37.3 dB 1251 11013 4 Locked QAM 256 7 441000000 Hz 8.4 dBmV 37.3 dB 1210 10991 5 Locked QAM 256 8 447000000 Hz 8.3 dBmV 37.6 dB 1391 9984 6 Locked QAM 256 9 453000000 Hz 8.0 dBmV 37.3 dB 1556 9849 7 Locked QAM 256 10 459000000 Hz 7.9 dBmV 37.6 dB 1361 11049 8 Locked QAM 256 11 465000000 Hz 7.7 dBmV 37.0 dB 1516 12217 Upstream Bonded Channels Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power 1 Locked ATDMA 1 5120 Ksym/sec 17300000 Hz 47.3 dBmV 2 Locked ATDMA 2 5120 Ksym/sec 23700000 Hz 46.5 dBmV 3 Locked ATDMA 3 5120 Ksym/sec 30300000 Hz 45.8 dBmV 4 Locked ATDMA 4 5120 Ksym/sec 36700000 Hz 45.3 dBmV You also need all the uncorrectables on there.zoom out the screen snip a little.
are you connected directly to the cm400 or is there a router in between? If so, which router?
zoom meetings are sensitive to upload speed as well. What upload do you get?
you say you're paying for 75mbps and get a 3rd of that. Do you have a screen snip of your speed? And how are you testing? wired/wireless?
Sorry for the incomplete screen grab. I now am attaching one with uncorrectables, which tend to be 7 to 9 times higher than correctables.
I am using Belkin N600 as the WIFI router. You questions led me to take additional troubleshooting steps. I found that the connection between the Belkin router and Netgear CM400 is a bottleneck. When I connect my MacBook to CM400 directly, the download speed increased from 20 to 80Mbps. The upload speed stays at 5-6Mbps. However, the Zoom video is still blurry and choppy even when the computer is directly connected to the cable modem. The other side has no problem seeing me though.
So the uncorrectables are a bit high. If you have any splitters, attenuators, amplifiers in line, remove them. If you still get that many errors, the isp needs to check the line.
And you know your speeds from the cm400 is at least 80mbps download.
Do you have a different device you can test with?
