Okay.
Emulations requires more horsepower than the original system.
Possible? Sure. Full speed? Doubtful.
GameCube was more powerful than the first xBox, thanks to its PowerPC CPU (look it up)
HD is a resolution, games aren't defined as HD by their lighting and shading.
You can't compare "ur mhz and ghz and ram" numbers on consoles, its more about the processor itself then the little number on the side.

I own all of lastgen systems as of October 2008. (Finally got a Dreamcast)
I own every currentgen system except PS3.







