cyberheater
PS4 PS4 PS4 PS4 PS4 PS4 PS4 PS4 PS4 PS4 PS4 PS4 PS4 PS4 PS4 PS4 PS4 Xbone PS4 PS4
The 360 and Wii U might use different SIMD (et al) instructions, as well. While they're both Power-based chips, different cpu lines can have different instruction extensions (like how AMD had "3DNow!" floating-point SIMD extensions, then Intel introduced their "SSE" instructions some time later; they were both x86 chips, but if you wrote code that used SSE math, then the 3DNow! chips would essentially have to just use the regular floating-point units to run similar calculations, and that's a lot slower).
Edit: That example is more extreme because it involved two different chipmakers using the same architecture, while our current situation involves IBM being the chipmaker in both cases
Pretty sure a decent compiler would take care of that. The majority of game code would essentially be the same.