"Here IE10 is 257% slower than the fastest browser 379pts vs 974pts)" I would say something slower can be 0-100% of the faster thing. Being 100% slower means it

"Here IE10 is 257% slower than the fastest browser 379pts vs 974pts)" I would say something slower can be 0-100% of the faster thing. Being 100% slower means it does nothing at all. I would define IE 10 as being 61.1% slower and Firefox as being 157% (not 257%) faster. 100% is double the speed, 200% is triple the speed, which it's not. "A 9% improvement is still 248% slower..." That's saying that if A is 257% faster than B and B speeds up by 9%, A is 248% faster than B. I don't agree. 974/379 = 2.57. Increase the 379 by 9% -> *1.09 = 413.1. 974/413.1 = 2.35. Which means Firefox is 135% faster after IE's 9% improvement.