After spending some days in the company of the latest iPhone models, Anandtech summarized today what it has experienced and measured so far. Besides A9 SoC benchmarks, Anandtech points to a special yet undiscussed feature of the iPhone 6s: storage. It’s not the 16 GB storage option but the solution Apple has used: it has integrated a unique storage solution yet unseen in any mobile device, which propels the devices ahead of every OEM in the industry, Joshua Ho notes in his blog entry. Let’s see what Apple did.
Apple uses custom NAND controllers for storage in the iPhone. In the case of the iPhone 6s, it has taken the MacBook SSD controller and adapted it for use in the smartphone. The main difference between the two is that the iPhone’s NAND controller uses both PCI-E and NVMe, making it the first mobile solution to use both.
Here’s Ho’s technical explanation:
The controller is a critical part of any storage component, but without any NAND to control it’s a bit pointless. Fortunately, the NAND used appears to be exposed in the OS as it’s referred to as 1Y128G-TLC-2P. Breaking this down, the 1Y means that we’re looking at 1Ynm NAND process with TLC. The TLC portion might concern some, but as we’ll soon see it turns out that we’re looking at a hybrid SLC/TLC NAND solution similar to SanDisk’s iNAND 7232 eMMC and desktop SSDs like Samsung’s 850 EVO which is better suited to the bursty workloads seen in mobile and PC segments.
The best thing about such hybrid SLC/TLC NAND solutions is (in essence) that the SLC cache is large enough to “avoid showing the reduced performance of TLC NAND,” Ho explains. But you only have to take a look at the charts inserted below, and the numbers will convince you about the iPhone 6s’ impressive performance.