Pentium 4
- High clock rate which means it
- ran very hot
- wasn't optimized for mobility
- not a notebook processor
Pentium M
- A "mobile" processor
- Optimized for battery life
- Specifically targeted for laptops
Nehalem vs. Sandy Bridge
Sandy Bridge uses a smaller nm technology for its circuitry over Nehalem, and on a per-clock basis there is some improvement in speed (< 20%). Other than that you won't find the large difference you found when going from Pentium 4 to Pentium M.
What will give you a big difference in battery life, power, and maybe even form factor is switching to Sandy Bridge and going with a SSD instead of a HDD. Battery life will be a lot longer, you'll use less power (with the same or better performance), and it may even be lighter.
Thanks for your answer. But I could just get a SSD w/o Sandy Bridge. So you are saying that the difference in battery life due to Sandy Bridge alone are small? – Daniel Gehriger – 2011-02-13T21:18:52.137
Compared to Nehalem? Yes. If you have a Nehalem processor or are thinking of getting one, just go with that. – aqua – 2011-02-13T21:20:12.863
I should also mention that it depends what sort of Sandy Bridge processor you get. If you get a very high-performance processor compared to a lower-power consumption processor, that obviously makes a difference, since even within SB there are differences among processor classes. – aqua – 2011-02-13T21:22:31.397