What is better On board sound or a sound card?

Generally speaking, onboard sound is pretty good. It's come along way since the old days. However,there is no argument that a decent soundcard would be better. Moreover, alot of onboard sound's features are implemented in software which requires CPU resources to run. If you have a dedicated sound card, that offsets the CPU's need to handle the sound. THis will not give you a significant change, but anything you can offload from the CPU is generally a good thing :P