Did you just say you locked it to 1600? That would be very bad, since you never need 1600mhz all the time. browsing and idling you will need only 800mhz or less. no wonder your computer is so hot. your battery life is also probably a lot less.
I bought a 1.6ghz macbook air and not a 800mhz one. And yes, I notice a big difference between these 2 speeds, programs like photoshop, safari and itunes start much quicker now.
My computer is 35C while browsing, only when i watch a video on youtube or play a game its 85C. But atleast it wont stutter or anything, even 1080p movies play smooth.
The 65nm chips in the first revision were just not efficient enough to be used in such a small casing. Yes, I should have waited for the reviews, but after seeing the keynote I went to the store and bought it immediately.
I've tried numerous undervolt tools on windows xp, like rmclock, but when the temp reaches 75C it clocks down to 1200mhz.
Run the Everest stress test and check the cpu speed for yourself.
It looks like there is no tool that is compatible with the air which can turn off all the 'safety' features apple has put in place. I dont understand why apple did this, because the CPU will clock itself to 1200mhz when it reaches 100C anyway.
Now when i play a game on bootcamp it will play smooth the first 3 minutes, then the temperature reaches 85C and the framerate drops because the CPU is running at 1200mhz