Have received e-mail from xfinity increasing my speed from 50 Mbps to 100 early 2017. Speed remained at 50 Mbps. No improvement whatsoever. Renewed contract in October including 100 Mbps. Representative stated I needed new modem which I received. Still no improvement. Last week received e-mail increasing my speed to 150 Mbps. Re-set modem, unplug , etc. Still getting 50 Mbps. Representative stated wi-fi speeds will not approach advertised speed.So, am receiving 50% of what am paying for and 67% less than offered. Any help would be appreciated as Comcast either has inept reps or do not care.
Depending on your Router (WIFI) and the card in your PC determines how fast the connection will appear. If your router doesn't have 5Ghz or it isn't working that would be 1 reason. If your card inside your PC is not capable of 5Ghz that would be another reason. The 2.4Ghz band maxes out for speed at 54Mmps.
Provide your router make/model to verify speed capability
Provide the wifi card info to see if it's obsolete or note
Also, run the speed test with your PC connected to the modem with an Ethernet cable and you should see the higher speeds.