Replacing WebStar cable Modem with Linksys CM100

not sure what SRN is but this is what I found on the Webstar: (signal noise ratio?)
Downstream Channel
The data shown in the table below provides information about the signal coming from the network to your cable modem.
Downstream Status Operational
Channel ID 3
Downstream Frequency 627000000 Hz
Modulation 256QAM
Bit Rate 10496000 bits/sec
Power Level 4.4 dBmV (This means that RR is not having a lot of issues sending a signal to your modem. If it were say 8-10 on average then issues could be there. Anything over 10 and most likely your modem will burn out soon trying to keep up.)
Signal to Noise Ratio 37.8 dB (This means the clean signal versus dirty signal is pristine. SNR should be between 30 - 40 dB)
Upstream Channel
The data shown in the table below provides information about the signal being transmitted to the network from your cable modem.
Upstream Status Operational
Channel ID 4
Upstream Frequency 36000000 Hz
Modulation 16QAM
Bit Rate 2304000 bits/sec
Power Level 46.5 dBmV (This is the power levels used by the modem to sync up with the RR head end. It should always been a higher number for upstream than downstream. This is fine as long as it stays stationary and doesn't jack up over 50-55).

More than likely when you get disconnected these numbers probably drastically change and go flippant. As soon as the disconnect occurs I'd get on the phone with RR to see what they see on their end with the new modem in place.

Here are the levels on my Webstar modem, I have not had one dropped connection since the line tech came out.

Name

WebSTAR DPC2100R2
Modem Serial Number



00:1a:c3:5c:e5:64
Hardware Version

2.1
Software Version

v2.0.2r1256-060303
Receive Power Level

6.0 dBmV
Transmit Power Level

44.4 dBmV
Cable Modem Status

Operational

I have ordered a SB6121 hoping it will get my speeds where it needs to be

If speed is just your issue, I would guess you have node issues in your area. I know in mine my node is overutalized because speeds suffer a ton when people get home from work etc. If I try it at 2am speeds are fantastic. A new modem won't help this, an ISP that properly manages their network will.