I think if we need a quite long battery life and still cheap solution, don’t go for dual core or even core 2 duo processor, see http://asia.cnet.com/reviews/hardware/notebooks/0,39001749,39133705,00.htm
The TravelMate no doubt impressed due to its exceptional battery life. Using MobileMark 2002, a rating of 364 minutes was attained which is comparable with the HP nx5000 which holds one of the highest ratings for mainstream notebooks.
Performance-wise, the 4001LMi clocked a performance rating of 163. This compares favorably with other mainstreams with a 1.5GHz processor such as the NEC Versa E2000 with a score of 148 and is almost on par with the HP nx5000’s score of 161.