I'm on preferred service here in Henderson NV with an old Motorola SB5120 modem and was told upgrading to a DOCSIS 3 modem would improve performance. To that end I checked the compatibility page, ordered the SB6141 and placed a call to support last night to have it provisioned. Before the switch I was getting about 20mb/down and 5mb/up according to speedtest.net.
After the switch, it was backwards, I was getting 1mb/down and 20mb/up. After spending TWO hours on the phone with tech support, rebooting, bypassing everything and plugging my laptop into the modem the tech finally "gave up". He was very patient but ultimately could not make it work. He blames the modem as being faulty but the lights indicate proper operation. Reading other threads I see there may be a config problem. He did try and send config updates (numerous times).
The final answer was "exchange it". We switched back to the old modem and after another call got it working. Three hours later, back where I was when I started.
I really doubt this modem is defective, it powers up, connects, works, except for the speed being backwards (slow down, fast up).
Other than just connecting my laptop and running speedtest.net (and getting a wide variety of IP addresses), he never asked me to look at anything on the modem's config page (not that I know how to do that).
Reading other threads here I see other problems that may or may not be related but don't really understand the solution.
Can anyone here help? I really would like to get upgraded (although at this point I'm not sure why).