Concerned: What hardware and OS are you using? As noted in the Airfoil documentation, an Intel Chip-based Mac (ICBM) and Mac OS X 10.5 (Leopard) are recommended. The issue is that DVD playback alone uses a great deal of resources, and we then have to capture it, hold it, and replay it. This is really something where faster hardware and newer software is the best answer, coupled with not doing much/anything else on your machine (quit other CPU intensive apps).