The old A5 found in the iPhone 4S and older versions of the iPad 2 (pictured left) and the new improved A5 system-on-a-chip found in the new Apple TV and recent iPad 2 models (pictured right).
Apple updated the Apple TV earlier this year, beefing up the little set-top box’s streaming power to 1080p and introducing a single core A5 processor to the mix.
Or so we thought.
Chipworks has finally gotten around to tearing down the device's custom-made A5 system-on-a-chip and made an interesting discovery. That single core A5 is actually a dual-core chip with one of the two A9 cores “turned off.” Apple is actually using a new 32-nm process for the Apple TV’s die production, which is down from the 45-nm process used for the iPhone 4S dual-core A5 processor.
The new A5 processor die is not a single core processor, but contains a dual core processor. Either Apple is only utilizing one core or they are binning parts. Parts binning is a common process in semiconductors where devices are segregated (binned) based on meeting a subset of the overall requirements, in this case they could disable the “bad” core, this increases the usable die per wafer, lowering the cost. — Chipworks
The new A5 measures nearly 41% smaller than its predecessor, coming in at 69.6 mm². Process shrinking not only reduce costs by fitting more dies on a wafer, but it also improves performance and lowers power consumption. This is a very complex chip for a relatively low volume part (for Apple); one would think they have greater plans for this new A5 variant. — Chipworks
Chipworks even opened up a recent iPad 2, and lo and behold it contained the same A5 chip found in the new Apple TV, presumably with both A9 cores enabled. Chipworks is in the process of checking their iPhone 4Ss as well.
Source: Chipworks [via MacRumors]