Battery life with i3 vs. i5 vs. i7

Question

I recently purchased a laptop with an i7-640m processor (blinded by a discount), and my battery life is fairly horrendous: the manufacturer given battery life is 6 hours (I know, it's an upper bound), and I barely squeeze out 3 hours with light usage+wifi. I can't seem to find any information on whether swapping out the processor for a i5 or even an i3 would significantly extend the battery life, aside from people baldly asserting "it should extend battery life" and my own intuition.

Has anyone tried to quantitatively compare these processor families with respect to battery life?

Note that the upper-bound on the battery life was probably with the default i5 configuration, and that my laptop heats up very quickly and stays hot, possibly pointing to more power dissipation than the laptop was designed to handle. I should also note that Engadget gets around 5.5 hours with a similar usage profile, for a i5 configuration. The TDP is exactly the same for all three (i3-3xxm, i5-5xxm, i7-6xxm)

Solution 1

This forum thread has an interesting summary:

http://forum.notebookreview.com/hp-envy-hdx/501066-envy-14-battery-life-log.html

The envy 14 shipped with i3, i5, and i7. The 6+ hours from the i3/5's seems to be mostly from people that just ran their battery down while doing nothing, but on average it seems that i7 yield a lower battery life by a noticeable amount.

Of course, this is talking about the i7-720m, which has 4 cores. The difference between i5 and i7-640m might not be so noticeable. Hmm.

Solution 2

can't seem to find any information on whether swapping out the processor for a i5 or even an i3 would significantly extend the battery life,

It doubt it would. 3hrs is about average.

. I should also note that Engadget gets around 5.5 hours with a similar usage profile, for a i5 configuration

Different battery capacity, most likely.

Comments

[Moab]

Battery life is always overstated by Notebook manufacturers, I always cut them in half for real word numbers.

[David Schwartz]

I doubt it will make much difference given that the TDP is the same.

[Pylsa]

I think 3 hours is even quite a long time ;) Mine won't last for even 2 hours with i5.

[oded]

My i5 Sony Vaio has an interesting feature built in that further reduces the battery working time by stopping charging at 80% !! You can disable it but as I mostly work with mains power connected I've left it in "battery care" mode as it supposedly prolongs the life of the battery.

[100rabh]

@BloodPhilia My Envy lasts about 4hr on IGP, it's got an i5. @BrianA IMO that is just marketing speak

[thenoviceoof]

@BloodPhilia, I'm just used to having a longer battery life.

[thenoviceoof]

doesn't seem like engadget was using an extended battery