Just curious, are you with Comcast?
If so, do you notice a speed increase at night compared to the daytime hours?
How can you check,
Speedtest.net - The Global Broadband Speed Test. It has been reliable for me when troubleshooting bandwidth issues.
If you are seeing a difference between your daytime and nighttime speeds, more than likely they are reallocating bandwidth from residential customers to their business customers. I see this when I'm working from home in the reduction in bandwidth and have complained to Comcast. They get an earful everytime I call as their CSR reps are crap.