Test your connection to a service like Netflix with and without CyberGhost VPN. If you consistently get better speeds with the VPN, then it would suggest that your ISP (which may also be your cable company in Comcast’s case) is throttling your connection. A tool called Wehe can also help you check if Comcast is throttling services like Netflix. It collects some data from your device, though, so it’s best avoided if you prefer not to share information like your phone’s operating system and your general location.