It will depend how you define “noticeable”….is it gonna make the difference between you winning or losing? Probably not unless it is a razor-thin margin at the line.
Will it reduce your overall watt expenditure for the race, leaving your fresher for the finish? Yes. Will it be “noticeable”? 
My Gen 1 Evade was definitely “noticeable” on my training rides, etc. Too much going on during a race for me to say if I “noticed” it or not.