Yeah but the way GTA's custom radio stations incorporate your music into the game world makes makes them fun and immersive in a way that playing mp3s in the background just isn't
It's not just playing back mp3 files. For example, if you leave your car radio on and leave your car, the game applies all kinds of environmental and spatial effects to the audio to make it sound like the music's blasting out of your car's speakers
Real-time audio processing is one of the more intensive things CPUs do, and when it gets out of realtime it's noticeable real quick and . Obviously there's some problem with how they've implemented calculating it versus the normal radio stations though. Weird the WAV conversion doesn't work, I'm positive I did that years and years ago. What patch level are you on?
75c is not that bad at all, it's well below TJ Max for like 99% of modern chips. This is just another walk in the park for laptop users who are used to seeing like 100c when playing games, lol. I'd definitely prefer my game to not eat up my entire computer for playing a custom radio station, but it's not like it's going to cause nuclear meltdown.