Windows 10, LAN on MB (10/100/1000). MoCA filter and splitter where cable enters house - one leg to video distribution box, second leg directly to my modem. Had 200 MB plan and was getting around 180 MB. Upgraded plan to 1200 MB and modem (Arris SB8200, DOCSIS 3.1), Cat 6 directly from desktop directly to modem port just to test - would "spike" speed to around 700 MB then immediately throttle down to 320 MB - 380 MB. Reset and reprovisioned modem twice. No change. Had Comcast Tech out who checked speed at pole (1200 MB), speed at tap for house (1200 MB), speed at modem (1200 MB) with "excellent power levels" per Xfinity Tech. Add SB8200 in the mix and speed drops to 320-380 MB. Tech said "Speeds based on our equipment. SB8200 might not hold full boot file. Try our Xfi modem." Did that - same speeds. Would spike to around 600 MB then drop back to 320-380 MB. Hmmm, ok. Try another gig speed modem. Got a Netgear CM1200 yesterday. Set up with Cat 6 direct from desktop to modem. Testing wee hours of the AM and get a little better but not much - certainly not 1 GB.
Using speedtest.net app in W10 rather than browser test - Browser test is consistently 50-100 MB slower. Modem reports:
Startup Procedure
Procedure
Status
Comment
Acquire Downstream Channel
627000000 Hz
Locked
Connectivity State
OK
Operational
Boot State
OK
Operational
Security
Enabled
BPI+
IP Provisioning Mode
Honor MDD
honorMdd(4)
Downstream Bonded Channels
Channel
Lock Status
Modulation
Channel ID
Frequency
Power
SNR
Correctables
Uncorrectables
1
Locked
QAM256
32
627000000 Hz
7.8 dBmV
41.2 dB
0
0
2
Locked
QAM256
1
435000000 Hz
6.3 dBmV
40.6 dB
0
0
3
Locked
QAM256
2
441000000 Hz
6.1 dBmV
40.5 dB
0
0
4
Locked
QAM256
3
447000000 Hz
6.3 dBmV
40.5 dB
0
0
5
Locked
QAM256
4
453000000 Hz
5.9 dBmV
40.5 dB
0
0
6
Locked
QAM256
5
459000000 Hz
5.8 dBmV
40.5 dB
0
0
7
Locked
QAM256
6
465000000 Hz
5.4 dBmV
40.4 dB
0
0
8
Locked
QAM256
7
471000000 Hz
5.5 dBmV
40.4 dB
0
0
9
Locked
QAM256
8
477000000 Hz
5.5 dBmV
40.4 dB
0
0
10
Locked
QAM256
9
483000000 Hz
5.8 dBmV
40.5 dB
0
0
11
Locked
QAM256
10
489000000 Hz
6.1 dBmV
40.5 dB
0
0
12
Locked
QAM256
11
495000000 Hz
6.4 dBmV
40.4 dB
0
0
13
Locked
QAM256
12
507000000 Hz
6.7 dBmV
40.5 dB
0
0
14
Locked
QAM256
13
513000000 Hz
6.8 dBmV
40.6 dB
0
0
15
Locked
QAM256
14
519000000 Hz
6.3 dBmV
40.6 dB
0
0
16
Locked
QAM256
15
525000000 Hz
6.6 dBmV
40.8 dB
0
0
17
Locked
QAM256
16
531000000 Hz
6.1 dBmV
40.8 dB
0
0
18
Locked
QAM256
18
543000000 Hz
6.1 dBmV
40.7 dB
0
0
19
Locked
QAM256
19
549000000 Hz
6.1 dBmV
40.7 dB
0
0
20
Locked
QAM256
20
555000000 Hz
6.7 dBmV
40.9 dB
0
0
21
Locked
QAM256
21
561000000 Hz
7.1 dBmV
40.9 dB
0
0
22
Locked
QAM256
22
567000000 Hz
7.4 dBmV
41.1 dB
0
0
23
Locked
QAM256
23
573000000 Hz
7.4 dBmV
40.9 dB
0
0
24
Locked
QAM256
24
579000000 Hz
7 dBmV
40.9 dB
0
0
25
Locked
QAM256
25
585000000 Hz
6.8 dBmV
40.8 dB
0
0
26
Locked
QAM256
26
591000000 Hz
6.5 dBmV
41 dB
0
0
27
Locked
QAM256
27
597000000 Hz
6.1 dBmV
41.1 dB
0
0
28
Locked
QAM256
28
603000000 Hz
6.9 dBmV
41.2 dB
0
0
29
Locked
QAM256
29
609000000 Hz
5.8 dBmV
41 dB
0
0
30
Locked
QAM256
30
615000000 Hz
7 dBmV
41 dB
0
0
31
Locked
QAM256
31
621000000 Hz
6.7 dBmV
41 dB
0
0
32
Not Locked
Unknown
0
0 Hz
0.0 dBmV
0.0 dB
0
0
Upstream Bonded Channels
Channel
Lock Status
US Channel Type
Channel ID
Symbol Rate
Frequency
Power
1
Locked
ATDMA
1
5120 Ksym/sec
35600000 Hz
43.5 dBmV
2
Locked
ATDMA
2
5120 Ksym/sec
29200000 Hz
44 dBmV
3
Locked
ATDMA
3
5120 Ksym/sec
22800000 Hz
44 dBmV
4
Locked
ATDMA
4
5120 Ksym/sec
16400000 Hz
44 dBmV
5
Not Locked
Unknown
0
0 Ksym/sec
0 Hz
0.0 dBmV
6
Not Locked
Unknown
0
0 Ksym/sec
0 Hz
0.0 dBmV
7
Not Locked
Unknown
0
0 Ksym/sec
0 Hz
0.0 dBmV
8
Not Locked
Unknown
0
0 Ksym/sec
0 Hz
0.0 dBmV
Downstream OFDM Channels
Channel
Lock Status
Modulation / Profile ID
Channel ID
Frequency
Power
SNR / MER
Active Subcarrier Number Range
Unerrored Codewords
Correctable Codewords
Uncorrectable Codewords
1
Locked
0 ,1 ,2 ,3
33
678000000 Hz
7.7 dBmV
40.6 dB
1108 ~ 2987
107783651
105295721
0
2
Not Locked
0
0
0 Hz
0 dBmV
0.0 dB
0 ~ 4095
0
0
0
Upstream OFDMA Channels
Channel
Lock Status
Modulation / Profile ID
Channel ID
Frequency
Power
1
Not Locked
0
0
0 Hz
0 dBmV
2
Not Locked
0
0
0 Hz
0 dBmV
Extended Upstream Transmit Power
Enable Extended Upstream Transmit Power
Current System Time:Sun Mar 28 06:41:00 2021
System Up Time:13:47:03
I'm at a loss to explain why I'm not getting the plan's reported speed. I think I've isolated just about everything on the system except changing out LAN card in desktop but I'm thinking that's not it since I was briefly seeing 700-800MB before it dropped back down to 320-380MB. Coax cable from tap on line to modem - check (good - no interference, no power drop, per Xfinity Tech). Cat 6 - check (good, tried two different ones). Modem - Check (three different modems, three different manufacturers). Power levels in spec - check (Xfinity Tech confirmed).
I'm at a loss to figure this out. Hopefully someone will have an idea.
No Responses!