You guys are just talking past each other. Apple, just like everyone else, makes modifications/optimizations to the base ARM designs. Look it up on wikipedia if you like.
No, that's simply wrong. There's certainly nothing on wikipedia to back that up, nor anywhere in the industry press that I'm aware of. The A9 in the iPhone 4S is 100% indistinguishable from the same core in Exynos 4 or OMAP44x0.
You're right. All Cortex A9 chips are the same. What might differ is the fab process. A company could make it at 40 nm, another at 32nm and another at 28nm, so you would get further optimization from that as well.
Apple's A5X SoC is 50% bigger in surface than Tegra 3. Considering the Tegra 3 SoC contains 4 CPU cores, and Apple's A5X only 2 CPU cores, plus taking into account all that extra space, I could see how A5X's GPU easily doubles Tegra 3's GPU in size, if not more. That's where the performance increase is coming from. Hopefully Nvidia and others will be smart enough to build bigger chips with in the next generations.
Fabless licensees, who wish to integrate an ARM core into their own chip design, are usually only interested in acquiring a ready-to-manufacture verified IP core. For these customers, ARM delivers a gate netlist description of the chosen ARM core, along with an abstracted simulation model and test programs to aid design integration and verification. More ambitious customers, including integrated device manufacturers (IDM) and foundry operators, choose to acquire the processor IP in synthesizable RTL (Verilog) form. With the synthesizable RTL, the customer has the ability to perform architectural level optimisations and extensions. This allows the designer to achieve exotic design goals not otherwise possible with an unmodified netlist (high clock speed, very low power consumption, instruction set extensions, etc.).
"The A5 contains a rendition of a chip based upon the dual-core ARM Cortex-A9 MPCore CPU[10] with NEON SIMD accelerator and a dual core PowerVR SGX543MP2 GPU.[11] ... Among the customizations that Apple has done to the chip is the inclusion of an image signal processor unit (ISP) that will do advanced image post-processing such as face detection, white balance and automatic image stabilization[14] and an "earSmart" unit from Audience for noise canceling"
Look I'm no expert but it's been often reported in the press about the A4 and moreso the A5 that Apple made optimizations to them. PA Semi was originally often attached to such reports but I think later reporting often cited the Intrinsity acquisition.
Here's a comparison of the A5 and the reference ARM Cortex A9 design:
IMO it's important to distinguish between creating a custom chip by integrating off-the-shelf IP cores and creating custom IP cores.
Looking at the CPU core itself can be a little complicated. IIRC, Apple was using the Intrinsity version of the Cortex-A8 which can be viewed either as customized (since it wasn't the vanilla Cortex-A8) or as off-the-shelf (since Apple/Samsung apparently didn't make any additional modifications to the Intrinsity version). http://www.anandtech.com/show/3665/apples-intrinsity-acquisi...
Now that Intrinsity is part of Apple, if we assume that they're still applying Intrinity's dynamic circuit technology to the Cortex-A9 then you could say that Apple has a customized version of the Cortex-A9.
Also, Apple has an ARM architectural license (from the Newton days AFAIK) that allows them to add new instructions and such, but they have apparently never used it.
This is starting to feel like debunking a conspiracy myth, so I'll let this be my last update (except to point out that you're deliberately misrepresenting what I said. Again, sigh.:
First link says that A9 is sold as synthesizable IP (duh), not that Apple made modifications. Second that Apple integrated a separate DSP core (a completely unrelated subject). Third just shows that they did indeed synthesize it (any change of floor plan is going to produce an completely different layout for the same circuit).
Is there any evidence at all that Apple made secret-sauce changes to the A9? There certainly aren't benchmarks of any kind to show it. Any new features? Anything at all that the posited "Apple A9" does differently than all the dozen others out there in the wild? No.
Someone says they know someone at Apple and they are working on "designing future chips"
You: Apple doesn't design anything, it's all off the shelf.
Me: I'm pretty sure he means Apple's modifications to the base stuff.
You: No, there's nothing in wikipedia that indicates Apple modified anything.
Me: here's two wikipedia links and other citations showing the changes Apple makes and how that might be expected for some ARM licensees.
You: They maybe didn't change one part I want to talk about, I win.
For the record I think you are correct that it hasn't been shown that Apple has made radical changes to the A9 CPU. It also hasn't been shown to my knowledge that they haven't made changes. There certainly are benchmarks where Apple's chip does better then other A9's but there's no evidence this is hardware based.
Most importantly, I don't care if they changes they're making are to other parts of the SoC or to the core A9 CPU design. Changes to the SoC perfectly qualify under what you originally replied to "future generations of chips" before the gratuitous display of nitpicking and goalpost moving.
