Best configure to get best battery life while great performance?

I am about to purchase an Envy 14 and battery life and performance are really important for the laptop to meet my needs. Here are the specs im looking at:

i5-460M
640GB 7200RPM
4GB of RAM


I have two main questions. I know getting a quad core processor can really kill your battery life and was wondering how much of a difference is there between the different levels of i5 processors in terms of power usage? I have looked at the specs for the i5's and they all seem to use the same amount of wattage (35W) but have heard that some can give you longer battery life somehow.

Also, would a 7200RPM drive use more battery life than say a 5200RPM?

Any help would be greatly appreciated!

 

You will not notice any significant difference between the various i5 processors in the Envy lineup.

A 7200 RPM drive will definitely use more power than a 5200 RPM drive ; but there is a noticeable speed difference.
I would go for SSD if possible (much faster and lower power use)

 

I think the difference in power usage in the levels of i5 is very little only because the higher levels might heat up a little quicker therefore using the fan more, and the fan uses power..but it shoudnt make much of a difference anyway. I agree on the SSD, but it would only make a difference of about 15-30 min depending on what you're doing

 

not at all, the higher the chip in one line the best power usage it has.

Its simple you have a TDP limit, which is 35w, and the chip shouldnt cross that threshold, so you get a higher clocked chip working within the same parameters.

Now more to the point, people who usually swap the CPU, with a higher model (within the same line) get lower temps. I will point out again the usually.

 

For that matter, a faster chip will complete the task faster, meaning it can return to an idle state sooner and take less power. Higher performance does not always correlate with higher power consumption.