When word got out that Titanfall would weigh in at 48GB on the PC, I kind of assumed that requirement had to do with super-high-res textures or the like. Well, that's not the case. According to Eurogamer, the game actually owes most of its massive footprint not to high-res textures, but to uncompressed audio.
To be precise, the PC version of Titanfall reportedly includes "a whopping 35GB of uncompressed audio."
Respawn Entertainment, the game's developer, claims the uncompressed audio was included for the benefit of slower PCs. "A two-core machine would dedicate a huge chunk of one core to just decompressing audio," says Richard Baker, Respawn's Lead Engineer. "We couldn't dedicate those resources to audio." The Xbox One decodes audio in hardware, so it has no such limitation.
As hesitant as I am to second-guess people who do this sort of thing for a living, I can't help being a tad dubious. Does audio decompression really require that much horsepower, even on a slow system? I suppose it's possible that Titanfall simply needs a lot of CPU time for game logic, and the developers simply couldn't spare the CPU cycles needed for audio decode.
Either way, those of us with mid-range and high-end PCs will have to put up with a 48GB game install without any real payoff—and that, if anything, is the disappointing part.