Why does I7 get worse battery life than I3?

https://news.ycombinator.com/item?id=9744842

by vezycash • 11 years ago

1 2 11 years ago

news.ycombinator.com

I know I7 consumes more power than I3. But my question still remains.

Is it impossible for the processor to throttle itself on lower load e.g. Web browsing, document typing? I.E. If I'm just browsing, why can't I7 last as long as I3?

Better still, can't users get a SWITCH to optimize for battery life or power.

SP3 spurred my question. Many would love the I7 version for the horse power. But would have to settle for considerable less battery life.

Can't Intel make some changes that would allow more powerful processors to last as long as the less powerful ones at lower load?

Lastly, am I the only one who desires this?

PaulHoule• 11 years ago

When a CPU is made they can change the process parameters to affect the voltage range it works at and the speeds it works at. So some of the difference is baked in, and this is the point behind the BIG/LITTLE architecture.

As for power management, this seems to be the new way computers rot. What tends to happen is that you get more background processes that get in the way of turning the power down. That and the way lithium batteries lose capacity over time.

I have a "desktop replacement" laptop that runs Windows and I have a profile where the CPU is limited to 15% and I usually use that when I am putting it on my lap because I don't want to get burned.

Ardeof• 11 years ago

When looking at a comparison of an Intel i3-4370, and an Intel i7-4790k (coincedentally, the score difference is about double...), you'll notice that the 4790k actually gets about double performance at 88W, in comparison to half the performance of the 4370 at 54W. This shows that the efficiency of a 4790k is actually greater than a 4370. Part of the reasoning behind that is because while the cores and the threads double (As well as the Smart Cache), the GHz ratio lowers overall, even though the 4790k has a higher clock rate. This makes the efficiency of the CPU much better than the i3 being compared.

So realistically, the i7 is actually a better option when using CPU intensive tasks, while the i3 is preferable when doing simple tasks such as browsing online. So while the maximum watt draw of the i3 is a flat amount, the i7 can potentially draw 30W more, which could cause a significant drop in battery life.

Another issue with watt usage could be because of the extra 2 cores. The i7 would basically be keeping both cores powered and ready, which could cause some extra watt usage even when not needed.

Look into Power Options, as well as CPU throttling and turning off cores if the extra Watt usage is that much of a bother.

Why does I7 get worse battery life than I3?

Related Stories