The only time faster hard drive accessing makes a difference is when you actually have to access the hard drive.
That is when
-you have HUGE textures (Skyrim)
-for some coding error you have to access the hard drive while gaming (rarely but sadly happens e.g Assassins Creed 3 if memory serves well)
But aside from these times (a.i. when all data is already in your memory) the effect is not significant.