How are M3, M5 and M7 chips achieved?

[Mike Boreham]

Are the M3, M5 and M7 chips:

a. Different by design, manufactured separately?

or

b. All the same design, manufactured on the same line and tested after to see if they should be categorised M3, M5 or M7?

 

[curmudgeonette]

b. All the same design, manufactured on the same line and tested after to see if they should be categorised M3, M5 or M7?

This is called "binning". The chips are tested so they can be placed in the proper "bin". However, just because a chip was placed in a lower bin, doesn't mean that it was incapable of higher bins: Once all orders for a higher bin are filled, everything else goes in the lower bin.

Also note, the exact same silicon sold as Y-series chips (aka m3 and etc.) can be packaged differently and sold as 15 watt U-series chips. (Apple doesn't use any of those. The U-series that Apple uses in the MBP is a different chip.) Once again, testing "bins" the chips as needed: Power misers may end up as Y-series, power hogs as U-series.

 

[Mike Boreham]

This is called "binning". The chips are tested so they can be placed in the proper "bin". However, just because a chip was placed in a lower bin, doesn't mean that it was incapable of higher bins: Once all orders for a higher bin are filled, everything else goes in the lower bin.

Also note, the exact same silicon sold as Y-series chips (aka m3 and etc.) can be packaged differently and sold as 15 watt U-series chips. (Apple doesn't use any of those. The U-series that Apple uses in the MBP is a different chip.) Once again, testing "bins" the chips as needed: Power misers may end up as Y-series, power hogs as U-series.

Thanks for the extra info about "binning".

From what you say I assume this is what happens with the M3, M5 and M7 chips for the MacBooks?

If so, it is a complete lottery what performance any given computer will have. Although on average M7 s will be faster than M5 s, some M5, or even M3 machines could be extremely close or even faster.

I would be pretty unhappy if I shelled out for an M7 which only just scraped it to the M7 bin, and very chuffed if my M5 was really an M7 level chip which was classified as M5 because they had met the quota for M7 s that day.

Might explain why my 2016 M5 has a higher Geekbench score (6386) than usually quoted (e.g. 5724 in Mactracker) for 2016 M5.

....is there another factor I am missing like an M3 which has an M7 chip is clocked down to the M3 spec levels?

 

[Falhófnir]

Thanks for the extra info about "binning".

From what you say I assume this is what happens with the M3, M5 and M7 chips for the MacBooks?

If so, it is a complete lottery what performance any given computer will have. Although on average M7 s will be faster than M5 s, some M5, or even M3 machines could be extremely close or even faster.

I would be pretty unhappy if I shelled out for an M7 which only just scraped it to the M7 bin, and very chuffed if my M5 was really an M7 level chip which was classified as M5 because they had met the quota for M7 s that day.

Might explain why my 2016 M5 has a higher Geekbench score (6386) than usually quoted (e.g. 5724 in Mactracker) for 2016 M5.

....is there another factor I am missing like an M3 which has an M7 chip is clocked down to the M3 spec levels?

I believe as intel's 14nm process is now quite mature that more chips will perform to theoretical spec, so will be potentially 'M7 standard' - though will end up being clocked lower if classed as an M3 or (now i) M5 - that in itself doesn't necessarily mean much though as I believe above the m5 clock speed in the 6th gen chips would cause quite dramatic throttling, which could make the m7s ultimately no faster then the m5s.

AMD go even further, their Ryzen 5s are just Ryzen 7s with some of the underperforming cores disabled! To make a '6 core' chip out of an 8 core where not all of the cores function to spec!

 

[curmudgeonette]

....is there another factor I am missing like an M3 which has an M7 chip is clocked down to the M3 spec levels?

A chip that could have been an M7 but was sold as an M3 will be limited to M3 clock rates. ... However, its power profile may be different than a "real" M3. It might be better or worse. It is simply guaranteed to meet M3 specs - which are likely overly broad to cover a wide production variety.

To head off your next question: Today's chips have a small amount of PROM/EEPROM/Flash that configures the enabled feature set. Intel has a long list of features that can be enabled/disabled this way. A desktop i7 will enable hyperthreading, while an i5 disables it via the configuration data - but you don't know if the even/low/left threads or odd/high/right threads are disabled. BTW, the configuration memory will have a cell that when flipped, prevents any further changes. This means that a well performing M3 cannot be reconfigured into an M7.

 

[Mike Boreham]

A chip that could have been an M7 but was sold as an M3 will be limited to M3 clock rates. ... However, its power profile may be different than a "real" M3. It might be better or worse. It is simply guaranteed to meet M3 specs - which are likely overly broad to cover a wide production variety.

To head off your next question: Today's chips have a small amount of PROM/EEPROM/Flash that configures the enabled feature set. Intel has a long list of features that can be enabled/disabled this way. A desktop i7 will enable hyperthreading, while an i5 disables it via the configuration data - but you don't know if the even/low/left threads or odd/high/right threads are disabled. BTW, the configuration memory will have a cell that when flipped, prevents any further changes. This means that a well performing M3 cannot be reconfigured into an M7.

Thanks very much! Not sure I would have thought of the next question, but interesting.

Bottom line is that my initial superficial concern (that "binning" meant that a good M3 might be just as fast as marginal M7) is completely unfounded.

 

[EugW]

It should be noted that while in short benches the m7 may be fastest, under sustained load the m7 last year throttled to under m5 speeds.

https://www.notebookcheck.net/Face-Off-Apple-MacBook-12-Core-m3-Core-m5-and-Core-m7.172046.0.html

It should also be noted that the 2017 m3 is as fast as the 2016 m5, although in Notebookcheck's m3 review, it did show some odd behaviour with short episodes of throttling after about 15 minutes. I'm not sure if it was just their sample though.

Overall though, the 2017 m3 is a great chip. The i5 does offer some advantage, but in terms of the MacBook, the main benefit of the 2017 i5 model is the increased SSD size, not the CPU performance.