In addition to the aforementioned information, there is also a "peak usage period" that can affect things that need a lot of steady bandwidth. Peak usage period is when the highest number of people are on the service, and that usually occurs in the early to late evening (about 6PM to 10:30PM EST for me) and early to mid morning (about 6AM to 8AM EST for me). The speeds can dip and not be as steady during this period due to the system having a finite throughput and that throughput having to be divided between more users. Sort of like when you get more cars on the road during rush hour. Overall, things can slow down.