Well here goes. Mr. non-expert giving a reply. Swing speed is one of two factors that determine how far you can carry a ball. Of course the faster the club travels equates as to how far the ball goes with a qualification. The qualification is that you must make centered contact. Ideally the ball carries farthest when you hit it on the sweet spot and the clubhead is directly on the line of flight and neither open or closed. If you carry the ball 270 with a 115 mph swingspeed you probably, based on my limited reading, are getting pretty much all you can get. ( give or take ten yards and between 2.2 to 2.5 factor of club speed vs. carry)
Myself, I really have not evaluated swing speed other than what the little indicator tube placed on a shaft reads. My drives on the course are in the 240 to 270 yard range, given soft fairways and maybe 10/15 yards of roll. I use a 10.5 degree metal head and a True Temper TT-Lite steel shaft cut at a littles less than 44"