iPad Pro iPad Air 2 with 3 cores V 9.7" iPad Pro with 2 cores?

[aces99]

I got a question regarding the new iPad Pro. The new 9.7" iPad Pro has 2 cores while the iPad Air 2 has 3 cores. How come the Air 2 has more cores than the new Pro and what would be the difference between them. You would think that the new Pro would have more cores than the older version. Any Pro's know why.

 

[Atomic Walrus]

The individual cores on the A9X SoC are significantly faster than the cores of the A8X. This basically means that 2 A9X cores can beat 3 A8X cores.

Because many workloads are not well threaded (don't take advantage of multiple cores) the faster single-core speed makes the A9X the better performer.

You're probably still asking, "why not use 3 A9X cores and make it even faster?" The answer is that the iPad is thermally limited by its passive (no fans) cooling. Adding a 3rd core wouldn't have any significant effect.

When you check Geekbench scores you'll see that the single core comes in at about 3200, while multi-core scores something like 5500. So even with 2 cores there's already some heat or power based throttling, and adding a 3rd core wouldn't likely make any tangible improvement.

 

[Abazigal]

I got a question regarding the new iPad Pro. The new 9.7" iPad Pro has 2 cores while the iPad Air 2 has 3 cores. How come the Air 2 has more cores than the new Pro and what would be the difference between them. You would think that the new Pro would have more cores than the older version. Any Pro's know why.

You can try reading this article for more insight.
http://www.anandtech.com/show/9766/the-apple-ipad-pro-review/2

The fact that Apple dropped back down to 2 CPU cores is unexpected given that we don’t expect Apple to ever go backwards in such a fashion, and while we’ll never know the official reason for everything Apple does, in retrospect I’m starting to think that A8X was an anomaly and Apple didn’t really want a tri-core CPU in the first place. A8X came at a time where Apple was bound by TSMC’s 20nm process and couldn’t drive up their clockspeeds without vastly increasing power consumption, so a third core was a far more power effective option.

My guess is power consumption. Apple has traditionally favoured 2 faster cores over more slower ones because that's what matches the workflow for most people using their devices.

 

[joeblow7777]

More cores doesn't always mean better performance. There are android tablets and phones with 8 processor cores that don't out perform iOS devices with 2.

 

[masotime]

I dunno. if you're going to call it "Pro" it's good to have more cores for stuff like 4K video editing which can benefit from multiple cores.

Perhaps one day we'll have dual-core, quad-core and hexa-core options for iPads, à la Mac Pros.

 

[aces99]

Thanks for the link, it was an interesting read. Sounds like the A9X is a beast. Can't wait to get my 9.7" Pro. It's going to be a long week.

 

[tarasis]

The individual cores on the A9X SoC are significantly faster than the cores of the A8X. This basically means that 2 A9X cores can beat 3 A8X cores.

Because many workloads are not well threaded (don't take advantage of multiple cores) the faster single-core speed makes the A9X the better performer.

Though seemingly the A9X in the 9.7" Pro seems to throttle down faster and harder than the A8X Air 2 does. I've just been running the 3DMark Sling Shot Extreme test on both devices, and over 11 tests one after another the Pro has basically dropped 500 points where the Air 2 is only down 140. Something I wasn't expecting at all.

(Benchmark, no demo, wifi on, brightness 50%, volume at zero, true tone off, night shift off, auto brightness off)

Pro 9.7           Air 2
3088                  1932
3027                  1917
3050                  1918
2862                  1923
2929                  1929
2768                  1926
2670                  1904
2741                  1875
2621                  1825
2716                  1800
2600                  1793

If I run the benchmark again, this time with the Demo on then I've seen the figure wobble about. First run had the Pro on 2392 (well below the average of 3037), where the Air 2 managed 1915 (just a little under its average of 2054).

I hadn't been looking for a reason to not keep the device, but now I'm a little unsure and certainly a bit disappointed.