There are three major areas that make one sound card better than another. The first is the capability that it gives your speakers that are connected to it. Many times, simply buying better speakers will make your computer sound better. However, because Dolby sound is such a big deal right now – especially when watching movies or playing video games – some of the sound cards are moving to this sound expertise. So if you have speakers that allow for Dolby Surround Sound, but your sound card will not work that high, then you might want to invest in a new sound card that will allow for this increased output of sound. Also certain sound cards only are able to handle certain speak configurations. A low-level factory sound card might be able to go left-right stereo, and perhaps a low level output of a powered sub-woofer, while a higher-level sound card will allow a 7 speaker system to have a different sound coming out of each speaker for a more full sound.
The second consideration in getting a sound card is simultaneous speech. Many higher-level games use this new sound technique. It simply allows for a different sound wave to come across for each voice, rather than smashing them into a single sound. This may not seem like a huge deal, but the ability to break apart the sound rather than grouping it together makes music, and different audio effects crisper. The third thing to look for, and listen for when trying out a sound car, is the ability to make a not as good sound into a better one. When you put in a movie like Top Gun or an older MP3 you will notice a sound difference from newer movies and music, however some sound cards will actually increase the quality of these older files.