Speed gains will vary depending on the bow, how the strings were made, how many strands, etc. etc. etc.

Art, yours were "ropes" compared to what a lot of folks like with the low stretch materials, but I personally don't like tiny strings, and I've heard about the tiny 450+ strings not holding up, so........

FWIW, I've heard about a 20+ fps gain on one bow when the string was changed, but that one was the exception. The same string material used on a different bow lost 5 fps--go figure. I didn't make the strings on either one, but the fellow that did make the strings (and chrony'd the bows) knows his stuff.

Chad