I need a powerful VoIP program because I need to talk to different people around the world at the same time. Ventrilo can accommodate many people in one server.

Gamers  often use Ventrilo to communicate with other players on the same team of a multiplayer game because it uses minimal CPU resources.

Also, communicating by voice - as opposed to chat - gives a competitive advantage by allowing players to keep their hands on the mouse and keyboard, and communicate quicker than typing messages to one another.

In a fast phase game in which you don't have time to type to your keyboard, voice communication is a must and Ventrilo is my choice.