cable signal strength and quality

[MasterHoss]

I've been renting my cable modems from Comcast for quite a while now. Ever since they gave everyone 3Mbps throughput, I noticed that the SB5100 modem I had from Comcast never went much above 1Mbps (monitored using Net.Medic). Since the modem was giving me grief due to the need of it constantly needing to be reset, I called Comcast and asked them to replace it. They gave me an RCA DCM235 and that modem constantly achieves 3Mbps.

I went back and forth between the Motorola and the RCA and the results were consistent. throughput with the Motorola < 1.5Mbps and throughput with the RCA > 3Mbps.

Well, the RCA is starting to die on me--it needs to be reset every day now... and when I do need to reset it, it takes about 20 minutes of unplugging and plugging in the power cord.

I'm about to just go and buy an SB5100, but I konw I'll be faced with less throughput. Anyone confirm this? Anyone found any fixes for this issue?

 

[Trente]

I'm using a good ol' SB4101. I think it is basically identical to SB4100 but with minor changes. Nevertheless, it works flawlessly: I have never unplugged it from anything, so it is always on or in stand-by when I don't need it. Eitherway, you can't go wrong with Motorola when it comes to cable modems, IMHO.

 

[Praetor]

Honestly, I would stay away from any rca cable modem. As soon as I find out that a customer has one, I automatically swap it out for a different modem.

As for your 5100, I think there were issues with that particular model line, you might want to try getting a 5120. That's the model that we use in our system and at least for the past 6 months (approx when we "upgraded" to this model) I haven't noticed any of them just FUBAR'ing on their own.

I'm actually fond of my good old 3100, made back before they invented silly standby buttons. Running strong 24/7/365 since I got it back in 98/99. Unplugged only 5 times, each time due to either a move or severe electrical storms outside.

 

[MasterHoss]

Thanks for the replies. Praetor, actually, I moved to a new apartment in late May of this year and the Comcast installer came with a brand new 5120. I told him that I had problems not being able to achieve 3Mbps using the 5100 modem.

Well, I experienced the same problem. It's really weird... the Comcast guy brought out his laptop and he was hitting 3Mbps... I was definately below 1.5Mbps. He then brought up an RCA and I immediately was able to reache 3Mbps. We then tried the 5120 one more time and sure enough, I was stuck below 1.5Mbps again.

I guess my question is... anyone else out there running into this problem? Comcast + 5100 family cable modem + nForce2 onboard LAN = throughput being halved??

 

[MasterHoss]

Anyone have this problem?

 

[Thor86]

With my ISP up here in Canada, I always get consistant speeds with my SB5100, and no issues whatsoever. You may want your ISP to do a line test and make sure there isn't too many dirty signals.

 

[Praetor]

Hrm. Both motorola and rca's have the built-in, user-accessable diagnostic page. http://192.168.100.1

The 5100 also has a USB port on it, have you tried doing it that way to compare the speeds?

 

[MtnMan]

The maximum speeds are downloaded by the cable modem from the cable provider. When a cable modem powers on it does a DHCP request to the providers server to obtain this information. The downloaded settings should show using the link on the post above. I have an old SB2100, but it runs fine at 3 Mb because the downloaded configuration from my ISP sets it to 3 Meg.

 

[Trente]

Originally posted by: MtnMan
The maximum speeds are downloaded by the cable modem from the cable provider. When a cable modem powers on it does a DHCP request to the providers server to obtain this information. The downloaded settings should show using the link on the post above. I have an old SB2100, but it runs fine at 3 Mb because the downloaded configuration from my ISP sets it to 3 Meg.

You forgot the fact that when an RCA modem is used by OP he gets the proper bandwidth, so it's not something to do with the ISP.

 

[kurisu]

You need to call Comcast and verify that your QoS is set accordingly for the type of modem you have. There's a very good chance that it's still stuck on what was standard in the past [1.5mbps]..

They may also need to reset the modem. Definitely call Comcast, this is not a common issue - I troubleshoot these modems on 3.2 down connections daily without such errors.

 

[raildogg]

I have a 5100, and so far its been awesome. It stays cool, not like my Toshiba modem which got soo hot.

Its been very stable and fast.

 

[MasterHoss]

kurisu. Thanks for the suggestion. I may try that. I just got back from a holiday weekend... the RCA seems to be "back to normal" again but I think it's time I go purchase the 5100 modem again and give it another go using your suggestion.

I'll keep you guys updated.

 

[MasterHoss]

UPDATE: Well, I went to the CC yesterday and purchased another SB5100. I am still consistently getting under 3Mbps throughput. I tested by downloading MS Win2k SP1 and the latest nVidia unified drivers. With the RCA, I'm able to download at 310+KB/sec. With the Motorola, I'm definately under 100KB/sec (with very rare bursts over 100K). For the majority of the time, I'm hitting ~500K surfing/downloading with the SB 5100. With the RCA, I was over 2500K the majority of the time.

I called Comcast and they verified everything was set up correctly. They even had me connect the cable modem directly to the cable outlet instead of going through a splitter.

I just reset my cable modem and speeds have stayed the same.

My upload speeds are not an issue. I consistently achieve 250K which is what I was doing with the RCA.

So what do you guys think? Any suggestions?

EDIT: In case you guys ask, my firmware version is: SB5100-2.3.1.3-SCM00-NOSH Which is close enough to the newest version to no be an issue.

 

[imported_GoHack]

Please disregard. I misread the original post.

 

[MasterHoss]

bump...

Everyone using this cable modem actually receiving 3Mbps?

 

[MasterHoss]

Well, I give up. I'm returning the SB5100 yet again and using the "good" ole RCA DCM235.

To give you an idea of what I'm talking about as far as my problem goes, I have provided links:

1. 1.) RCA DCM235 cable modem downloa...west version of WinAmp
   2.) Motorola SB5100 cable modem do...west version of WinAmp

Yes, I tried downloading the file mulitple times with both cable modems. Yes, I tried downloading other files multiple times. Yes, I even did bandwidth tests from dslreports.com. I always had Net.Medic running in the background to verify these results.

 

[nyc79st]

I'm in a simalar situation too.
My trusty toshiba (that I rented from comcast) died Saturday, so I went to Circuit City and bought a Motorala SB5100.
My downloads are ranging from 700k to 1meg, up is okay (around 260k).
I think I'll call comcast today.
b.t.w my downloads with the old toshiba was around 3meg!

 

[raildogg]

Originally posted by: MasterHoss
I've been renting my cable modems from Comcast for quite a while now. Ever since they gave everyone 3Mbps throughput, I noticed that the SB5100 modem I had from Comcast never went much above 1Mbps (monitored using Net.Medic). Since the modem was giving me grief due to the need of it constantly needing to be reset, I called Comcast and asked them to replace it. They gave me an RCA DCM235 and that modem constantly achieves 3Mbps.

I went back and forth between the Motorola and the RCA and the results were consistent. throughput with the Motorola < 1.5Mbps and throughput with the RCA > 3Mbps.

Well, the RCA is starting to die on me--it needs to be reset every day now... and when I do need to reset it, it takes about 20 minutes of unplugging and plugging in the power cord.

I'm about to just go and buy an SB5100, but I konw I'll be faced with less throughput. Anyone confirm this? Anyone found any fixes for this issue?

the sb5100 is probably the best modem out there right now. very stable and stays cool all the time. I leave mine on all the time, of course and it never runs hot. Never had any problems with it

 

[MasterHoss]

raildogg: How does your statement help me again?

 

[Garion]

Originally posted by: Praetor
Honestly, I would stay away from any rca cable modem. As soon as I find out that a customer has one, I automatically swap it out for a different modem..

I've had the same RCA cable modem for 4+ years (the old @home). I have never had any problems with it and I don't believe it's throttling my bandwidth in any way. Once I got the service tech to tell me how to do a power down and re-synchronize to the cable (unplug power cable and network cable, plug in power and wait a few mins to re-plug in network cable) I was good. It loses sync about once ever 4 months and I have to repeat, but other than that, NO problems.

- G

 

[Praetor]

Originally posted by: MasterHoss
Well, I give up. I'm returning the SB5100 yet again and using the "good" ole RCA DCM235.

To give you an idea of what I'm talking about as far as my problem goes, I have provided links:

1. 1.) RCA DCM235 cable modem downloa...west version of WinAmp
   2.) Motorola SB5100 cable modem do...west version of WinAmp

Yes, I tried downloading the file mulitple times with both cable modems. Yes, I tried downloading other files multiple times. Yes, I even did bandwidth tests from dslreports.com. I always had Net.Medic running in the background to verify these results.

Wow. That's just bizarre. Did you load up the signal page I mentioned previously? Would you be willing to pass along those values you're seeing?

I know this doesn't help you any, but with all of the installs I've done, I've always had the best luck with Motorola's. I'm getting 5.5 mbit downstream off of mine right now.

Else, try a different nic in the same computer? Or have a service tech come out to look at the lines? It could be something that only affects the moto but not the rca.... Or, just stick with your rca.


I'm used to actually doing all these things myself, physically being there and doing everything, it's kinda hard for me personally, to troubleshoot like this. Hopefully you get this issue resolved though.

 

[MasterHoss]

Praetor: Sure. I'd be willing to pass along these values.

I've messed around so much with both cable modems and have called Comcast a few times to just delete all the registered modem profiles from my account. Ever since I had them do that, even my RCA is showing significant speed degradation. It's actually gotten so bad that my average throughput is down to 80K now.

I called Comcast 2 times last night and the last person I spoke with seemed a little more knowledgeable then the other reps. He assured me that my modem was registered with the proper 3Mbps profile. He pinged my cable modem and said he was returning 50ms responses.

I have to assume that something is just freakishly wrong with my onboard NIC. I'm going to stop and pick up a NIC on my way home today. I hope that solves all issues.

I also scheduled a tech to come out to my apartment this Friday which I would cancel if the new NIC resolves my bandwidth issues.

I'll keep everyone up to date.

 

[MasterHoss]

UPDATE: Well, it turns out that my onboard LAN was bad... so was my Cat 5 cable.

I picked up a Linksys LNE100TX NIC and also the Linksys Cable Modem tonight. I'm running the Linksys modem to test my throughput. I was very disappointed to see everything slow... I noticed that the Linksys modem even froze up... I just swapped out Cat 5 cables and, without rebooting the cable modem, the thing just became active by itself. Since that point, I've been downloading WinXP SP2 and other large files and getting ~2.7Mbps which is acceptable. I guess I'll try the Motorola SB5100 one more time since a lot of people swear by it.

Before I swap out the Linksys for the Motorola, anyone know which yields better performance and stability?

 

[Imyourzero]

Just thought I'd chime in and say that I've had an SB5100 running with Comcast for a few months now and I actually noticed a speed INCREASE from the RCA rental. I consistently get 260-340k depending on the server.

 

[MasterHoss]

Yeah. That was part of the reason for my concern. I've always read people saying how much the SB5100 was like the 2nd coming of Jesus as far as stability and throughput are concerned.

I actually did some searching off of Deja and found a handful of users that experience the same thing I did. EPoX nForce2 onboard LAN + Motorola SB5100 = phew, phew.

I'm still going to try the 5100 one more time... the Linksys cable modem seems to be working well for me. I'm going to try the SB5100 tonight and compare it to the Linksys. I may even try the RCA 1 more time.