Let's do this right. Winner's Choice what? In other words what material are you asking about. Almost all string makers prefer a certain material but will make strings with what you want. Some material is faster than others. Now if you're talking about a string made of BCY 8125, which is pretty standard, then you may gain some speed.

I got my string and cables about a month ago and headed for the shop. I chrono'd the bow at 272fps. Then went and changed the rigging and set the bow to the same specs and checked the speed again. The gain was 11 fps, more than I expected. My factory rigging was two weeks old and made of Brownell UltraCam.