I'm getting 17.8 down and 3.3 up which is about normal for me. I'd
call comcast and ask if there are any known issues in your area. If
there are none, here are some things you can check yourself to try
to track down the issue:
In a web browser, go to your cable modem's diagnostic page - usually
192.168.100.1 and check your signal strength. Upstream should be
<5 and Downstream usually should be between 35 and 45. If these
are out of range, then you will have very slow speeds.
If you have cable TV, check your splitter and filter (should be
where your splitter is) and see if either of those are bad by
bypassing them and checking your speed again.
If you don't have cable TV, there may still be a splitter in the
line with one end going nowhere or to an empty jack.
The line outside also could have been chewed on by TreeTards (read
squirrels) and have let moisture in the line or even broken the line
completely. Most lines are out of reach, but there are some sections
as it gets close to the house that you can visually inspect for this
kind of damage.
If you find problems with any of the above, call comcast for a
service tech to come out and replace the offending hardware. If it
is the splitter or filter, these can be bypassed to regain temporary
speed. If you don't have cable TV then neither of these items are
actually needed to be perfectly honest.
If all else fails, have comcast send a reset to your modem. This
actually does a little more than when you can do on your end by
unplugging power. If this doesn't help, then set up a service call.
There is a filter on the pole outside that has probably become
damaged and I don't
recommend that you climb the pole to fix it yourself.
I hope this helps you get your speed back!
Good luck!
Kevin