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Comment by tbarbugli | Hacker News Reader

I wonder what's the energy cost introduced by having 16 extra GB of RAM. Is that a space issue (more RAM = less space for batteries) or a power consumption?

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If I remember correctly it's not the ram that they're going for, but the processor the ram attaches to. The skylake low power mobile cpus all use the low power ram(as one would expect), and for some reason is limited to 16gb on mobile.

So if apple wanted the low power cpu, they had to limit everyone to 16GB.

All of the Skylake i7 mobile CPUs can handle at minimum 32GB and at most 64GB [0]

[0] http://ark.intel.com/products/codename/37572/Skylake#@Mobile

As per the processor data sheet [0] 32GB is only possible with DDR4, not LPDDR3.

[0] https://www-ssl.intel.com/content/www/us/en/processors/core/...

about ~1-1.5 watts under full load.

How about while idle? It seems like you'd still need a fair bit of power to refresh them, but I'd be interested to see the actual numbers.

For comparison the 13" MacBook Pro has a 50wh battery, so apple's 10 hour battery claim depends on the machine averaging 5 watts of power consumption during normal use. Adding 1 watt of consumption would reduce the battery life by 2 hours.

Something on the order of ~50-100 mW.

Even if that was the case, why not let users decide for themselves if they wanted 32GB and 8 hours of battery? 8 hours of battery is still pretty awesome.

I think the narrative that Apple presented about not giving the 32GB option because of battery time doesn't make much sense if you consider all the design decisions around these new machines. It makes more sense that Apple thought only a minority of users wanted 32GB and then it backfired.

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