Let me address many issues at once:
The resolution the console supports has almost no effect on the size of the files stored of the disks.
the only way it could is if the developers added hi res textures for using when in higher resolutions...which doesn't really happen.
If you look at most x-box games, the disks are only like halfway from the middle (which is about 1/4 of the storage) which is about 1.2 gig
I believe that Nintendo's biggest mistake with the gamecube is the disc format.
not true, the smaller disks are indeed very hard to pirate, also because they are smaller they can spin at a much higher speed meaning much better load times (i have never experienced load times greater than 2-4 seconds).
if you compare this with the load times for halo.....
It would have been so easy to use DVDs
yes it would but:-
a) that would have made the console alot bigger, maybe not as big as the X-Bulk but still alot bigger
b) playing dvd's would have increased the consoles value but also the price as they would have to pay a licence to the owner of the DVD patent to use the technology.
this is something that microsoft figured, if x-box was out of the box dvd ready they would have to pay huge royalties, thus you have to buy the dvd addon.
Xbox is using up a lot of space for Dolby audio and such which is nice and all, but really makes for some bad load times.
the x-box dvd's don't contain and DD (dolby digital) sound except for in cutscenes.
the DD signal is encoded in realtime by the console (giving far inferior quality to studio encoded dvd's)
also, DD was created to fit 6 channels of sound onto a film strip, it is a compression method and takes up very little space (not much more than 2 channel stereo)
There is supposedly a Japan version which is coming out that will actually play dvd movies too (it's a redesigned larger case that plays movies or the GC games).
this special edition
gamecube is made by panasonic and can be imported for about £500 ($700 USD) which is pricey but it is a badass gamecube
i think overall nintendo have made a very good decision about their disks and it is reflected in the sales figures (Nintendo is beating x-box sales by 50% over here)
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