As controversy over the functional defects of the iPhone 6+ have been growing, Apple has decided to stop its use of triple-level cell (TLC) NAND.
According to industry sources on Nov. 6, the U.S. smartphone giant has decided to discontinue its use of triple-level cell (TLC) NAND, since the company believes that the functional defects plaguing the 64GB iPhone 6 and the 128GB iPhone 6+ stem from a problem in the controller IC of the TLC NAND flash. The controller IC in question is reportedly made by SSD maker Anobit, which was sold to Apple in 2011.
TLC NAND flash is a type of solid-state NAND flash memory that stores three bits of data per cell. It can store three times as much data as single-level cell (SLC) that stores one bit of data, and 1.5 times as much as multi-level cell (MLC) solid-state flash memory that stores two bits of data. On top of that, TLC flash is more affordable. However, it is also slower than SLC or MLC in reading and writing data.
As a result, Apple is planning to use MLC NAND flash in the 64GB iPhone 6 and the 128GB iPhone 6+ in the future. The company will reportedly improve products already equipped with TLC NAND by providing the iOS8.1.1 update within the year.
The U.S. tech giant is riding high in Korea, as it already sold 100,000 units of the iPhone 6 and iPhone 6+ on the release date (Oct. 31) alone. Some mobile carriers already sold out of 64GB and 128GB models. Additional supplies are expected to be possible as early as this month.
MLC NAND was used in the 16GB version of the iPhone 6 and iPhone 6+ and some of the 64GB models, but LC NAND was used in all of the 128GB models. Apple apparently used TLC NAND to reduce costs. Previously, some iPads featured TLC NAND.
Meanwhile, an increasing number of Korean consumers are complaining about functional defects of Apple's latest smartphones. A growing number of the 64GB iPhone 6 users posted in online communities related to the iPhones about their request for product replacements due to slow speeds.
In such a situation, it is getting popular among users to find out whether MLC or TLC NAND was used in the phone through the speed measurement.
On Nov. 3, some overseas IT media sources speculated about the possibility of a potential recall of the iPhone 6+. Sources considered that since technical defects mainly occur in the 128GB version of the iPhone 6+, there might be a problem in the controller IC of triple-level cell (TLC) NAND flash.