Lets say a laptop with a CPU change would get 6 hours on battery. Being the competitive market it is, the battery size will be cut to get 3+ hours. There is no firm relationship of CPU to battery time since this cause and effect kicks in.
Be sure you line up your perspective laptops on a spreadsheet and fill in what the stock battery give you and if they offer a supersized battery pack.
Do you know of a website or other place I can find out the relative merits of the various laptop CPUs ? Intel Celeron M , AMD Sempron 2800, Intel Centrino, Intel P4, AMD Athlon64, Turion64 others?
I have heard it said that the Celeron processor will do everything a P4 can just "slower". How much slower? worth the extra dollars? What penalty in battery drain?
I need to look at:
Processor power (generic - absent speed)
Battery draw/life per charge
What else ? ? ?