Droid has same chipset and clocks rock solid at 800mhz and most do not see problems at 1ghz (people have issues at 1.2ghz and 10 degree temp increase). Still, the battery on the N900 is weak enough without upping the clock.

Which brings up a point that the Droid lasts a few hours longer than the N900, even when overclocked to 800mhz (scaling 250 to 800). Similar mah sized batteries and Droid is on 3G all the time and N900 is on 2G. Apples & oranges I guess.

Wish I could OC my Arm11 7201 Probably would melt the G1