I've experienced problems with RealTek Audio drivers before, so it's worth poking at those to see if you can make things better there.

I've also used Asio4All as well, and was quite impressed with it. It's easy to uninstall if it doesn't solve your problem. Give it a shot. I don't think it will solve your problem but it's worth a try.

Next thing is to try to narrow down the source of your problem. Is it the player program? For instance, can you play audio or video with a different player program, and does that play without hitching? Is it the DJ controller? If you have the controller disconnected, does the hitching/sputtering stop? That sort of thing.