Slow speed issue on the modem is because of the following factors

» Low signal level

» Incompatible speed with the service provider

» Ethernet cable used for connection

Could you please let us know the above details to work on your case further.

http://arris.force.com/consumers/articles/General_FAQs/SB6190-Cable-Signal-Levels

I just bought a new SB6190 and can’t get better than 65mbps. I was told i had better than 1500 coming into the house. I spent 2 hrs on the phone with Infinity yesterday so I don’t think,... ‘incompatible speed with service provider’

And I replaced the ethernet cable twice.

frustrating !!

SB6190 is compatible with a maximum speed of up to 800 Mbps. I would suggest decreasing the speed plan and monitoring the performance.