How long before Apple EOLs the Macbook Air?

[johngwheeler]

Proof of throttling?

Observed in many professional reviews.

Which reviews?

I have read many rMB reviews and have not seen a serious study of perceived throttling.

By "serious" I mean graphs of CPU/GPU frequency, temperature and power consumption vs time, for a variety of documented test scenarios.

All CPUs will eventually throttle if there are pushed beyond their thermal limits over a long time.

The question is how long this takes, and whether it causes significant slow-down for typical use cases.

BTW, my definition of throttling is a reduction *below* the advertised base frequency of the CPU, e.g. 1.1GHz. The inability to turbo boost to the maximum frequency should not be called throttling, because turbo is essentially a "bonus", based on the CPUs ability to ramp up throughput on one or more cores if the current CPU thermal envelope allows it.

If someone can demonstrate the core-M running below 1.1GHz when under load, then we have evidence of throttling. (note that when idle, the CPU will often drop below its base frequency to save power - this is not throttling)

 

[newellj]

Thanks. That's good to know. Sometimes the theoretical of the spec sheets don't accurately reflect reality.

My own experience with Lightroom 1:1 preview builds and 100%/1600p jpg exports is that the rMB runs about 20% behind my rMBP on a half-hour operation. In other words, a file op that takes about 25 minutes on the rMBP takes about 35 minutes on the rMB. Whether that's a big difference or not is a personal call.

 

[motrek]

...
BTW, my definition of throttling is a reduction *below* the advertised base frequency of the CPU, e.g. 1.1GHz. The inability to turbo boost to the maximum frequency should not be called throttling, because turbo is essentially a "bonus", based on the CPUs ability to ramp up throughput on one or more cores if the current CPU thermal envelope allows it.
...

According to your definition, the rMB CPU may not throttle, but if it's running at its advertised clock speed of 1.1GHz, you have to admit that that's pretty miserable compared to the 2.7GHz turbo boost speed that the MBA can run at all day long.

 

[johngwheeler]

What is maximum long-term core-M frequency?

According to your definition, the rMB CPU may not throttle, but if it's running at its advertised clock speed of 1.1GHz, you have to admit that that's pretty miserable compared to the 2.7GHz turbo boost speed that the MBA can run at all day long.

Yes indeed! So maybe the question should be more general as in "how long can the core-M maintain turbo speed of greater than <x> GHz for?"

Realistically, I can't see any computer manufacturer could get away with throttling the CPU below its specified base frequency, because it would mean that their design was unsuitable for the chosen processor.

You are entirely correct that the ability to use turbo speeds for longer periods is a big differentiator. I'm curious to know how long the core-M can sustain varying turbo frequencies, and how this compares to the other Apple laptops.

e.g. 30 seconds at 2.4GHz, 1 minute at 2.2GHz, 5 minutes at 2.0GHz etc....

This would probably be more meaningful that Geekbench results, which I don't believe really do this kind of long-term testing.

 

[motrek]

...
You are entirely correct that the ability to use turbo speeds for longer periods is a big differentiator. I'm curious to know how long the core-M can sustain varying turbo frequencies, and how this compares to the other Apple laptops.
...

Don't know and it will be a little tricky to figure out, since it will depend on ambient temperature and the temperature of the CPU at the beginning of the test.

But if you can find a rMB and install Intel Power Gadget on it, and a program to load it down, then you can get some data on it pretty quickly.

 

[ItHurtsWhenIP]

Just buy what you want now. It's not like any laptop Apple sells is bad.

Two years ago I would've rolled my eyes at this..

After 20 months of MBA ownership I'm convinced that what you've typed is correct.

Whatever happens between now and when my '13 Air calls it quits, I'll be sure to replace it with something Apple is offering.