Wells continues, "All of these bugs point to the exact same problem in our streaming system. We are streaming stuff constantly; we're abusing the PlayStation 3 like a bad child. We're streaming audio, music, animation, video, levels, textures, everything. We're filling the memory, and about halfway through, it gets jammed up so that when we ask for a texture, it's not there; we ask for an animation, and it's not there." Balestra interjects to note that the reason this bug came up was because the programmer happened to play the game on an older test unit -- most of Naughty Dog's Quality Assurance team were using newer debug hardware and hence weren't running into this issue. The developers realized that a lot of fans still probably play games on launch-era PS3 systems, and this bug could end up ruining a lot of players' experiences.
Balestra remembers having an intense two-hour-plus discussion with lead programmers Travis McIntosh and Christian Gyrling to nail down exactly what triggers the game's meltdown at the halfway point, and they concluded that somehow, the streaming system was causing the PS3's hard-drive to fragment, which therefore led to lots of seeks when requesting data, and said seeks would cause the "traffic jam" that Wells described earlier. Wells notes, "Even though it's literally past the day that we told Sony, 'We're not changing the code anymore, trust us,' we went in and changed the most fundamental and frequently called function in the game."