Didn't use a parser, I bought 2 sets of mythrite gear and melded a ton of skill speed materia on to one of the sets so that the stats were the same for both except 1 set had more skill speed. The damage increased by 1 point (from doing 58-64 up to 59-65) this is between a 1.6-2% damage increase at 518 skill speed (354 + 164) so 164 skill speed is about a 2% increase.