New CM600 modem consistently gets slower speeds than Xfinity modem (on singlethreaded speed tests)

Question

Hi, I recently bought the CM600 cable modem hoping to cut out the modem rental that Comcast provides. I had their Xfinity Technicolor TC8305c modem previously. I have Blast! internet service that provides a max speed of 150mbps. After testing both modems, the new Netgear modem doesn't seem to keep up on singe threaded speed tests such as the one at http://speedof.me

Here are the details (average speeds):

Xfinity Modem

speedtest.net (multi) - 180 mbps

speedof.me (single) - 120-130 mbps

Netgear CM600

speedtest.net (multi) - 160 mbps

speedof.me (single) - 90 mbps

I've also ran several other tests where the netgear doesn't quite keep up.

The modem is updated to the latest firmware (V1.01.09) and seems to work well otherwise. I'm trying to decide if I should ignore this discrepancy or if there is an actual issue here. It's really bothering me though, so hopefully someone has some insight into what could be going on.

Thanks for any help someone can offer!

Below is the cable connection data from the modem:

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

Startup Procedure

Procedure	Status	Comment
Acquire Downstream Channel	621000000 Hz	Locked
Connectivity State	OK	Operational
Boot State	OK	Operational
Security	Enable	BPI+
IP Provisioning Mode	Honor MDD	IPv6 only

Downstream Bonded Channels

Channel	Lock Status	Modulation	Channel ID	Frequency	Power	SNR	Correctables	Uncorrectables
1	Locked	QAM256	4	621000000 Hz	-0.8 dBmV	39.3 dB	0	0
2	Locked	QAM256	1	603000000 Hz	-0.1 dBmV	39.6 dB	0	0
3	Locked	QAM256	2	609000000 Hz	-1.5 dBmV	39.0 dB	0	0
4	Locked	QAM256	3	615000000 Hz	-2.5 dBmV	38.5 dB	0	0
5	Locked	QAM256	5	627000000 Hz	-2.7 dBmV	38.4 dB	0	0
6	Locked	QAM256	6	633000000 Hz	-3.9 dBmV	37.9 dB	0	0
7	Locked	QAM256	7	639000000 Hz	-2.7 dBmV	38.4 dB	0	0
8	Locked	QAM256	8	645000000 Hz	-3.3 dBmV	38.0 dB	0	0
9	Locked	QAM256	9	651000000 Hz	-3.7 dBmV	37.6 dB	0	0
10	Locked	QAM256	10	657000000 Hz	-2.6 dBmV	38.0 dB	0	0
11	Locked	QAM256	11	663000000 Hz	-2.8 dBmV	37.7 dB	0	0
12	Locked	QAM256	12	669000000 Hz	-2.9 dBmV	37.7 dB	0	0
13	Locked	QAM256	13	675000000 Hz	-1.9 dBmV	37.1 dB	0	0
14	Locked	QAM256	14	681000000 Hz	-1.6 dBmV	38.8 dB	0	0
15	Locked	QAM256	15	687000000 Hz	-1.7 dBmV	38.7 dB	1	0
16	Locked	QAM256	16	693000000 Hz	-2.8 dBmV	38.0 dB	0	0
17	Locked	QAM256	17	699000000 Hz	-3.8 dBmV	37.2 dB	0	0
18	Locked	QAM256	18	705000000 Hz	-4.6 dBmV	36.5 dB	0	0
19	Locked	QAM256	19	711000000 Hz	-7.2 dBmV	34.2 dB	0	0
20	Locked	QAM256	20	717000000 Hz	-8.2 dBmV	33.3 dB	0	0
21	Locked	QAM256	21	723000000 Hz	-7.8 dBmV	33.4 dB	0	0
22	Locked	QAM256	22	729000000 Hz	-10.0 dBmV	31.9 dB	0	0
23	Locked	QAM256	23	735000000 Hz	-8.3 dBmV	33.2 dB	0	0
24	Locked	QAM256	24	741000000 Hz	-6.3 dBmV	35.2 dB	0	0

DarrenM · Answer

Hello dsuse

&nbsp;

Do you happen to have some kind of cable spliter if so try removing it. Sometimes it can cause issues on some modem and other can work just fine with it.

&nbsp;

DarrenM

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New CM600 modem consistently gets slower speeds than Xfinity modem (on singlethreaded speed tests)

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