Originally Posted by dulcamara
All of the sub 2.5lb machines I know of come with a weak battery. Sharp and IBM will sell you an extend-life battery, but that adds .5 lbs to the weight.
The Sharp MM 20 with the 5 hour battery comes in at 2.5lbs. The IBM X40 grows from 2.5 to 3.1. The small battery on the X40 is pretty useless, even on the low-voltage model.
On Mobile mode I get just over 3 hours out of my MM20, on regular mode it'll do around 2 hours 20 minutes. The MM20's Efficieon CPU runs so cool that the machine doesn't even have a fan, and doesn't start to get warm for well over an hour, and even then it's just lukewarm...