Verified answer

If you aren't using a dedicated audio computer, your system could simply be getting bogged down by other processes running in the background. So, start by disabling all unnecessary processes. That and adding more memory are two things that should immediately improve your computer's performance.

Also, your on-board audio solution may not be ASIO compatible. Try playing around with the other drivers.

If everything you're doing is in the box, then a high end sound card would be a waste of money. However, if you're using your setup to actually record audio, then a pro sound card would be money well spent.

Good luck!