MechCommander:
In (scroll down a bit) topic, you can see that RCP has ported his Emulator, TRWin, to the Pocket PC and got a FPS of 4-8, so it IS possible, even with the current Pocket PC's.
Now just wait untill the new PPC's are out, and then you can tell me again that it is not possible

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Just below RCP's post, Alqwerty posted a message about on what kind of system he played Zelda (N64) on a P100/Voodoo1 system (i know, he can't remember it exactly), but when we moved to WinXP, we needed a really good PC.
So i do believe it is possible, maybe not with the current PPC's, but definatly with the newer ones. (think about it, 700Mhz

)