I would say that if you have z-5300's with a soundblaster live, you'd see an improvement with a better card, probably won't be really obvious, but those speakers are pretty nice and would be a good match for a good sound card. Like my megaworks is a pretty good setup if I say so myself, but I bet your logitech's have higher fidelity sound, the megaworks is just to be loud in some respects. But yes, any dedicated card is probably better than integrated, but how much you want to spend on that dedicated card depends on the speakers you will be using them with