We'll see how it pans out, naturally theres lots of things other than pure CPU speed which may effect the final speed. PSX would be fairly heavy on data transfer between CPU and Memory so if theres a bottleneck between CPU/Mem etc this may cause a problem, again no idea if this will be better/same/worse than a GP2X. I doubt the N800/770 has ever been pushed in this way.

But as you said, specs wise, on paper the N770 is faster than the GP2X and the N800 should have some more to spare! Will be intestering to see how things pan out. Still a shame Nokia couldnt had given us 4 buttons on the right probably the only big reason why it's not crawling with emulators and ported games.