Battery saving (Iris Pro 5200) VS. discrete graphics (nvidia 750m)

[magbarn]

But the increase in battery life won't be that substantial. That's not speculation. That's factual.

The screen still consumes far too much power for idle power consumption to make any difference.

And unless Iris Pro scales its performance perfectly (that's impossible!), it'll still consume more power than HD 4000 or HD 4600 just handling the interface.

All in all, idle power consumption would likely stay the same (or increase slightly) with Iris Pro, and who would care about battery life under heavy load when you'd get less than 2 hours at max load either way?

Logic: battery is 95WHr, CPU (w/ "custom" Iris Pro) is likely 55W (I'll even ignore Turbo Boost here) + display and other components at nominally 10W (50-75% brightness). Calculation says you get about 1.46 hours with those parameters. Read: 1 hour and 28 minutes.

That's hardly better than the 2012 model.

Granted, the 2012 model at max load would be 45W CPU (ignoring Turbo Boost again) + 45W GPU + 10W display and other components. Calculation gives .90 hours, or 54 minutes.

You barely get an extra 30 minutes of battery life... but for obviously less graphics performance.

Not worth it at all IMO.

Also, I know my calculation is absolutely correct for the 2012 model because I have a 2012 model, and I have seen battery estimate as low as 54 minutes under Bootcamp when I stressed both the CPU and GPU with Battlefield 3 running at 2560 x 1600.

Granted, Iris Pro may be less of a jet engine at such an insane load, but I don't think it'd make battery life that much better for the rMBP 15".

One of the reasons the 2013 MBA's get much better battery life is that if the screen isn't being refreshed, the CPU & iGPU is allowed to go to sleep whilst the screen stays on. This wasn't possible with Ivy Bridge. Is this really low idle mode not available on Iris Pro Haswells?

 

[bill-p]

One of the reasons the 2013 MBA's get much better battery life is that if the screen isn't being refreshed, the CPU & iGPU is allowed to go to sleep whilst the screen stays on. This wasn't possible with Ivy Bridge. Is this really low idle mode not available on Iris Pro Haswells?

Ivy Bridge does the same thing.

The Macbook Air gets more battery life because the processors are much more power efficient (13W vs 17W), and the batteries are physically bigger (38WHr for 11" and 54WHr for 13").

For the rMBP to have noticeably more battery life, the battery would also have to be physically bigger. But if they make the battery bigger, they'd compromise cooling... because removing the dGPU actually doesn't allow them to reclaim that much space.

 

[JuanGarcia]

Iris Pro similar to 650m from macbook pro retina??? what???!!!! are you crazy?

No way, Iris pro from desktop (more powerfull than mobile version) is aprox 30% slower than regular 650m (735mhz) when current retina 650m have higher core speed (900 mhz).

 

[Vanilla35]

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[br3nt]

i missed the keynote part about the MBPr but reviews that pop up in the near future will be of help in this thread so i'm kind of bumping it

 

[RichardC300]

i missed the keynote part about the MBPr but reviews that pop up in the near future will be of help in this thread so i'm kind of bumping it

How nice of you.