The only thing that most people will need to know about Apple's A9 is that it's a whole lot faster than last year's A8. But for those of you who are more interested in chip design, Chipworks has unearthed an interesting tidbit: there are two different versions of the A9 chip, one manufactured by Samsung and another by Taiwan Semiconductor (TSMC). Most interestingly, Samsung's version (the APL0898) has a slightly smaller footprint than the TSMC version (APL1022).

There have long been rumors that Apple was dual-sourcing the A8 from Samsung and TSMC, but this is the first visual proof that we've seen of the practice. iPhone and iPad processors up to and including the A7 were all made by Samsung.

Apple buys other parts from multiple sources including NAND flash and RAM, but the SoC is a major component with bigger implications for performance and power. Chipworks promises a more in-depth look at how the two processors are different, but for now, all we know is that they differ in size.

We have no way to confirm whether the chips in our review samples were made by Samsung or TSMC. iFixit's teardowns found the Samsung version of the A9 in the iPhone 6S and TSMC's version in the iPhone 6S Plus, which makes sense—a larger phone has more room to spare for a larger chip—but that doesn't necessarily mean that all of the phones are being put together this way. In our testing, both the iPhone 6S and 6S Plus benchmarked nearly identically, and both behaved well during Geekbench's thermal throttling test.

For more information, our full review of the new iPhones is here.