i don't get this "loads a sound from disc" thing. i doubt it did that. most games have those sorta short term use assets in the ram. i'm sure the audio when entering a scripted cutscene can lag, cause it's gotta place the head on the disc there. this loading mechanism could create lil hickups, but it's not a big deal imo. sure, a faster access time to the asset can smooth that. that access is a thing you gotta share with your os tho. if the drive is busy doing some other stuff, you gotta wait those milliseconds. 
no doubt that defragmenting and keeping quick access data on the first partition removes head movement. it's a balance act for your partition man tho. and i know windows is always shoving the head to sh!t it's logs when the sh!t buffer overflows. stupid sh!t mechanic delay. it can torture your drive when your head is further into the drive on the second partition. gotta go out to sh!t and back in again. ms codeblock. a terrible dumpster. 
no doubt that defragmenting and keeping quick access data on the first partition removes head movement. it's a balance act for your partition man tho. and i know windows is always shoving the head to sh!t it's logs when the sh!t buffer overflows. stupid sh!t mechanic delay. it can torture your drive when your head is further into the drive on the second partition. gotta go out to sh!t and back in again. ms codeblock. a terrible dumpster.