From what I've gathered, Console loads go like this: XBOX (with a good disc drive)>GameCube 1.1>PSN>PS2>GameCube 1.0 (XBOX varies from being faster than GC 1.1 or slower depending on the type of disc drive. Samsung disc drives are the fastest). GameCube 1.0 has horrendously long load times that can take over a minute so GameCube owners should buy 1.1 if their copy has slow loads. Gamecube 1.1 saves over 35 minutes compared to 1.0 in any% so that shows the massive difference that exists between the two versions. The Japanese/Korean versions are all based on 1.1. 1.1 may not exist in PAL regions. The PAL GC version is faster than NTSC 1.0 from what I've heard but it is still slower than all other versions. XBOX loads can vary between consoles. Some XBOXes are faster than GC while others are slower. The fastest XBOX would be one with a Samsung disc drive (differences between A and B drives have not been tested).

XBOX also runs at a silky smooth framerate unlike the PS2 and especially the GC versions.