What model of modem do you have? If it's an SB6121 (or any 4x4 channel modem), try getting an 8x4 modem. You can easily exchange it at Wave's office if you're renting one from them (make sure you ask for an 8x4 channel modem), if you're not, this is a great modem for the price - »
amazon.com/dp/B00AJHDZSI/If you're using a 4x4 modem, other people who are using 4x4 modems will congest the 4 channels that other people's modems are using, but if you have an 8 channel modem, you should have more capacity when 4 out of 8 channels are congested (DOCSIS 3.0 modems are good at load balancing).
Before writing another rude reply towards me, please know that I'm only trying to help you with what I know, I'm not a Wave employee and I can't flip a magic switch to make your internet faster.