Capture cards ultimately let you outsource the performance hit of live streaming or recording video content to the device itself, so if you were previously using your computer to record or livestream, your performance will naturally be improved when offloading to a capture card instead. Regardless, many capture cards still come with system requirements as, like any process, they have some affect on your PC performance when used. As long as your machine meets the mark set by the device, you should be fine!