“To put this in perspective, AMD and Nvidia were already shipping
high-end 28-nm GPUs fabbed by TSMC as early as January 2012, although
not in particularly high volumes,” Kanter said.
32-nm high-K metal gate process became available, Apple was able to rev
up production of the A6X chip with superior graphics to drive the iPad 4
launched in September.
“Not only did the A6X offer substantially
better graphics performance than the previous generation, but the die
size is also considerably smaller, at around 123 mm2,” Kanter wrote.
used a ratio of FLOPs/pixel to measure Apple’s tablet graphics
performance, noting the iPad 3 delivered 198 FLOPs/pixel, far less than
the 381 FLOPs/pixel of the iPad 2. “Practically speaking, this means
that any 3D applications which were moderately taxing on the iPad 2
could not take advantage of the Retina display."
By adopting the
Retina display before competing tablets such as the Google Nexus 10,
Apple retained a leadership advantage at the risk of disappointing some
users with an under-power GPU in an unbalanced system, Kanter said.
As an owner of an iPad 3 since it was introduced I can assure you that graphics performance is not underpowered, in fact it plays smoother and with higher frame rates than the Nexus 7 tablet recently released.
The iPad 3 came out last Mar'12. The A5X in it had 2 CPUs and 4 GPUs. Samsung non HKMG 45 nm process was used to build it and the die was huge 165 mm sq. Just a few weeks later ( May '12 ) Samsung brought out its own Galaxy using 32 nm HKMG ! The iPad 4 was relaesed Oct '12 with the A6x in it still with 2 CPUs and 4 GPUs but built with 32 nm HKMG ( device shrink factor 2 ) and the die only 124 sq mm ( die shrink factor 1.33 ), so presumably 50 % more transistors, apart from having a more advanced design.
The root cause of the iPad3 being weak in graphics was that Samsung built the Apple A6 with their non HKMG 45 nm process. Even with 2 GPUs the die was huge and dissipated a lot of heat which is why Apple had to use a Heat Sink on top of the SoC. Several months after the iPad 3 Samsung brought out their own Galaxy S3 using their 32 nm HKMG process. A few months later Samsung used their new Fab process for Apple's A6 in iPad 4. This episode exposed Apple's vulnerability from depending on just one Supplier with its own ambitions.
The results from anandtech also shows a similar pattern. The chip is underpowered for the resolution and does not deliver comparable "fps" for the retina resolution vs standard 1024*768 resolution...
David Patterson, known for his pioneering research that led to RAID, clusters and more, is part of a team at UC Berkeley that recently made its RISC-V processor architecture an open source hardware offering. We talk with Patterson and one of his colleagues behind the effort about the opportunities they see, what new kinds of designs they hope to enable and what it means for today’s commercial processor giants such as Intel, ARM and Imagination Technologies.