The guys at AnandTech went diving into the updated Metal documentation right after the presentation of the new iPhone 6 and 6 Plus by tying up enough strands to be able to make a pretty accurate estimate of what the A8 chip is hiding inside : an improved version of the 64-bit ARMv8 architecture, Cyclone, running on two cores at 1.4 GHz; and a six-core PowerVR Series6XT GX6650 GPU.
This GPU model explains the second family added to the Metal program guide with support for ASTC (Adaptive Scalable Texture Compression), a next-generation texture compression format, and also offers the 1.5x speed increase over the previous generation indicated by the apple during the presentation. AnandTech
The most direct implications of having a GPU in this new series is greater efficiency, being able to run at full power for longer without the temperature spiking and performance sagging that often occurs. It also features improved fill rate and polygon generation for even smoother graphics, and optimizations for superior performance by running processes in parallel. Add Metal to the equation and the result is: power, power, and more power, not just for gaming.
Apple SoC Specifications Apple A6 Apple A7 Apple A8 CPU Swift 1.3 GHz
(two cores) Cyclone 1.3 GHz
(dual-core) 1.4 GHz enhanced Cyclone (dual-core)? GPU PowerVR SGX543MP3
(three cores) PowerVR G6430
(quad-core) PowerVR GX6650
(six cores) RAM 1GB LPDDR2 1GB LPDDR3 1GB LPDDR3?
With respect to the CPU, the moderate jump to 1.4 GHz versus 1.3 GHz for the A7 does not explain the 25% increase in power announced by Apple and confirmed by tests on Geekbench. A 100 MHz difference in the same architecture alone would only mean an 8% increase, so Apple has had to further refine the Cyclone design to create a significantly optimized version of it. According to Ryan Smith of AnandTech, squeezing another 16% is an impressive achievement considering how solid the A7 design already was and how little time has passed.
Apple SoC Evolution CPU Performance GPU Performance Transistor Size A5 ~13x ~20x 122m2 A6 ~26x ~34x 97mm2 A7 40x 56x 102mm2>1000M 28nm A8 50x 84x 89mm2 ~2000M 20nm
The final note is set by the RAM, which seems to be confirmed unchanged from the previous generation with 1GB LPDDR3 . Ear-pull for Apple. It’s one thing that iOS is highly optimized and runs smoothly, it’s another thing that you leave for next year improvements that you know you’re getting plenty of and you can stick this one in. If iPhone 6 and 6 Plus are a beast with that memory, what wouldn’t they be with twice as much? Not to obsess about it, but to keep it in mind.