First, a capture card is a device that accepts a video signal that allows you to capture high-definition video on an external device. There are two answers to this question and will depend on what hardware you are using to stream with. No, you do not need a capture card if you are streaming and gaming on the same PC. All of the needed processing and capturing is done internally so, a capture card is not needed. On the other hand, if you are using a dedicated streaming PC and are gaming on a separate PC or console then yes, a capture card is a must. The capture card acts as a link between the video that your main gaming hardware outputs to your dedicated streaming PC. Some of the most popular capture cards include the AVerMedia Live Gamer devices and the Elgato Game Capture devices.