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Arris SB8200 only getting 750-800Mbps (now 300Mbps)

Regular Contributor

Arris SB8200 only getting 750-800Mbps (now 300Mbps)

I made the jump to 1GB, purchased a new modem. No dropouts to speak of, just wondering if this SB8200 modem is capable of doing better than 800Mbps (one device hard wired direct)? Or if my signal levels need a bit of tweaking? See attachments/links.


NOTE: I have FOUR devices on my coax - Modem, 4K X1 box, and 2x cable card tuners. For the past 3 years they've all been running through a Comscope CSMAPDU9VPI, with terminators on the unused ports. Previously when trying a non-amplified splitter, my cable card Tv signals would be way out of spec, causing tv channels to pixellate and drop out.


Modem numbers:

Downstream Power = 9.1 - 12.1 dBmV

Downstream SNR = 40.9 - 41.8 dB

Upstream = 37 - 38 dBmV


Cable card tuner example number:

Power = 6.5 - 8.1 dBmV

SNR = 36.2 - 37.5 dB



Regular Contributor

Re: Arris SB8200 only getting 750-800Mbps

Channel ID's 41-48 seem to be the issue with all those errors. I also get tons of these items about Channel ID 48 in the modem log every day:

Date Time        Event ID    Event Level             Description

11/10/2020 05:37740101006"CM-STATUS message sent. Event Type Code: 16; Chan ID: 48; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=zz:zz:zz:zz:zz:zz;CMTS-MAC=zz:zz:zz:zz:zz:zz;CM-QOS=1.1;CM-VER=3.1;"


NOTE: I edited those MAC addresses for privacy.

Regular Contributor

Re: Arris SB8200 only getting 750-800Mbps

Anyone have ideas now?


I just removed the Comscope CSMAPDU9VPI powered splitter and installed a non-powered BAMF 4-Way splitter. Ran speed tests with the same one device WIRED directly to the modem and speeds are worse. Can't even get 300Mbps now!


Here are the new modem signal levels:


Channel IDLock StatusModulationFrequencyPowerSNR/MERCorrectedUncorrectables
20LockedQAM256507000000 Hz2.3 dBmV41.5 dB00
17LockedQAM256483000000 Hz2.6 dBmV41.6 dB00
18LockedQAM256489000000 Hz2.6 dBmV41.7 dB00
19LockedQAM256495000000 Hz2.4 dBmV41.7 dB00
21LockedQAM256513000000 Hz2.4 dBmV41.6 dB00
22LockedQAM256519000000 Hz2.7 dBmV41.9 dB00
23LockedQAM256525000000 Hz2.8 dBmV41.8 dB00
24LockedQAM256531000000 Hz2.8 dBmV41.9 dB00
25LockedQAM256537000000 Hz2.4 dBmV41.7 dB00
26LockedQAM256543000000 Hz2.3 dBmV41.7 dB00
27LockedQAM256549000000 Hz2.4 dBmV41.7 dB00
28LockedQAM256555000000 Hz2.5 dBmV41.8 dB00
29LockedQAM256561000000 Hz2.3 dBmV41.8 dB00
30LockedQAM256567000000 Hz2.1 dBmV41.8 dB00
31LockedQAM256573000000 Hz1.9 dBmV41.6 dB00
32LockedQAM256579000000 Hz2.1 dBmV41.8 dB00
33LockedQAM256585000000 Hz1.9 dBmV41.6 dB00
34LockedQAM256591000000 Hz2.0 dBmV41.6 dB00
35LockedQAM256597000000 Hz1.8 dBmV41.4 dB00
36LockedQAM256603000000 Hz1.7 dBmV41.4 dB00
37LockedQAM256609000000 Hz1.8 dBmV41.3 dB00
38LockedQAM256615000000 Hz2.1 dBmV41.5 dB00
39LockedQAM256621000000 Hz2.3 dBmV41.5 dB00
40LockedQAM256627000000 Hz1.8 dBmV41.1 dB00
41LockedQAM256633000000 Hz1.1 dBmV40.8 dB00
42LockedQAM256639000000 Hz1.3 dBmV40.9 dB00
43LockedQAM256645000000 Hz2.4 dBmV41.1 dB00
44LockedQAM256651000000 Hz4.3 dBmV41.7 dB00
45LockedQAM256657000000 Hz4.6 dBmV41.9 dB00
46LockedQAM256663000000 Hz2.5 dBmV41.4 dB00
47LockedQAM256669000000 Hz1.2 dBmV41.0 dB00
48LockedOther688000000 Hz1.9 dBmV35.5 dB215453120

ChannelChannel IDLock StatusUS Channel TypeFrequencyWidthPower
13LockedSC-QAM Upstream32300000 Hz6400000 Hz45.0 dBmV
21LockedSC-QAM Upstream19300000 Hz6400000 Hz44.0 dBmV
32LockedSC-QAM Upstream25700000 Hz6400000 Hz44.0 dBmV
44LockedSC-QAM Upstream38700000 Hz6400000 Hz45.0 dBmV