The XBOX has a shared memory architecture - meaning more memory could be allocated to the frame buffer - which is needed for 720p / 1080i resolutions.
The Wii doesn't have this. The lack of VRAM is the biggest reason why the Wii will struggle to do 720p.
720 --> 1280 x 720 pixels = 920,000 pixels (approx).
If the Wii *is* limited to only 3MB of frame buffer memory (unless there is some trick), that's just not enough memory.
Usually (at a minimum) you want 16bit colour + 8bit zbuffer (can be skipped sometimes) - and at least TWO buffer. Otherwise its drawing from the buffer as you are changing things. (maybe you can setup a buffer not in VRAM - but this may not work on the Wii very well - I don't have the exact docs, so not sure).
This also leaves NO memory for textures.
...
From a memory point-of-view - its possible - but very hard technically. It may also seriously cripple whatever you are doing quality-wise.
Gesta Non Verba
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