Instead of going back to the Comcast center and walking away with another DOCSIS 2.0 modem, I purchased a Motorola SB 6141 and had it activated. My tested speeds dropped from 35/5 down to between 3-8/4. I called into support and they correctly show it provisioned as an sb6141 and I can also see that on my Comcast account page. I asked for an escalation to tier 2 support to look at the issue, but haven't had any resolution so far. From reading though the other threads it looked like the 6141 problems had been somewhat resolved. Do I still need to ask to have the modem provisioned with a 6121 boot file?
I'm going to add some technical details in hopes of a Comcast tech helping out. I've tried phone support twice and the online chat 4 times with no luck... I did get one online technician who told me that the bootfile was provsioned for the "silver" Performance tier of service when it should be provisioned for Blast+. She supposedly fixed the bootfile, but I have no way of knowing. Here's the data I can pull together:
Shaper Probe Output:
DiffProbe release. January 2012. Build 1008. Shaper Detection Module.
I think the last chat agent must have done something to fix the bootfile, because it's working beautifully now. I am seeing 35M/6M full speeds through my router. I only wish they would have told me what the proper bootfile was so I would know to ask next time.
It may have been a bootfile issue, but nevertheless as was stated, the upstream power is too high and may cause you issues if it fluctuates any higher intermittently. This should be addressed regardless. In an effort to gain a bit more wiggle room, are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured ? Any splitters that remain should be high quality and cable rated for 5-1000 MHz, bi-directional, and no gold colored garbage from Radio Shack, Home Depot, etc.
If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then putting them back together again, then perhaps it's best to book a tech visit to investigate and correct.
my sb5120 docsis 2.0 modem gets 24Mb/s down & 4Mb/s up with powerboost.
i bought a sb6141 to get a more stable connection with bonded channels, but i got exactly the opposite. i was getting very high packet losses on the downstream. Shaperprobe couldn't even test the download because of packet loss. It was horrible.
I was pulling anywhere from sub-1Mb/s to 14Mb/s download. Upload was fine. I was getting 4Mb/s+ constantly. It was infuriating. I had the latest firmware on it, it was confirmed activated on comcast, but it just wouldn't work with the bonded channels. I put muy sb5120 back on and my connection is back to normal. I can actually view the internet at full speeds again. How terrible.
The connection in my apartment is pretty crappy though. Sometimes not all of my HD channels work. Before, this happened more often, but now they're all typically available. Might have to return the SB6141
It's an old house we just moved into. It looks like there is one splitter outside and one in the attic. The cable running into the house now looks like it's only RG-59 and will need to be replaced. My plan is to re-locate the cable which is coming in from the pole. Install a new ground block and from there homerun a new RG-6 cable over to a new high quality splitter. I'll re-post power levels after the new runs. Thanks for the input everyone!