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Comment by usefulcat | Hacker News Reader

I think at least part of the implied tradeoff is resolution vs. battery life. More pixels == more GPU computation == more power required.

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AIUI the backlight dominates the power consumption, so more pixels at the same physical size makes very little difference.

But sure, that's a lot more concrete. So are you unhappy with the battery life on this device? Does the laptop the grandparent was talking about have worse battery life than comparable models? Certainly I'm very happy with the battery life of my Surface Book (which is a lot better than that of the laptop it replace), so to my mind it's not a problem in practice.

more pixels requires more light, even on the same size display... So a 4K display the same size as a 1080p display will require 2-3x the light behind the display... I don't recall the exact amount extra, but it's not insignificant.. let alone the processing power to push those extra pixels.

>more pixels requires more light

[citation needed]?

More pixels means more circuitry in front of the backlight blocking light.

But to what degree? Blocking 2% vs. 1% of the light probably isn't noticeable; blocking 50% vs. 25% probably is. This might also be something that improves over time as process improvements reduce the overhead.

Potentially a lot. The iPad 3 requires 2.5x more backlight power (7 watts) for the same brightness than the iPad 2.

Thanks for quantifying that - the difference is 4.2 watts, which is huge. I wonder if the LED backlighting is getting any more efficient?

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