If I understand the i5/i7 in the SP4, the main reason to get the i7 is the IRIS 540 gfx processor, right? The i5 is the 6300u and the i7 is the 6650u. Besides the faster gfx processor in the i7, they kept the core count the same between the two and the i5 actually has a higher base speed but lower turbo speed and 1MB cache less? So how is it that if using the computer for web browsing and simple tasks, the i5 battery last longer? Is using the IRIS 540 instead of the 520 enough of a power save to boost the i5 battery life just a little? And while not GPU throttling from what I read, the i7 is hitting some sort of thermal limit and slowing down before the i5 would? Which I haven't encountered with any games I've gotten to load. That I could compare to a i5. So my question, as I haven't had a chance to try this yet as I'm not home. If I edit the power management and limit the processor MAX state on the i7 to something like 70 (which if I understand, doesn't mean 70% of MAX state, but close to it) would that help in over heating and even give it better battery life without doing some crazy under volting like some people are doing? but then I wonder if I make it too low if it'll need to keep the CPU ticking longer so it would warm up anyways? What I'm trying to do is find a way to make the SP4 i7 last longer while watching videos (.mkv,.avi files, not youtube) and web browsing. So when I go on a trip that's going to be 5hrs+ I should be able to watch like 2x2.5hr movies and still have battery.