What about removing the router and retesting with pc direct to cable modem.
Plus goto you're modem config pages and look at your Cable modem info. You should have 10240000 set as downstream bit rate
http://192.168.100.1/
Here's mine on 20Meg
Code:
Downstream Channel:
Downstream Status Operational
Channel ID 4
Downstream Frequency 331000000 Hz
Modulation 256QAM
Bit Rate 20480000 bits/sec
Power Level 0.9 dBmV
Signal to Noise Ratio 37.6 dB
Upstream Channel:
Upstream Status Operational
Channel ID 4
Upstream Frequency 37500000 Hz
Modulation 16QAM
Bit Rate 768000 bits/sec
Power Level 30.0 dBmV