There's no real reason to have a 64-bit chip in a smartphone right now.
Outside the thumbprint scanner mounted on the home button, one of the big selling points of Apple's new iPhone 5S launched last month is its 64-bit A7 chip, which is a first for a smartphone form factor. The chip is supposedly required to power the thumbprint scanner, and essentially paves the way for future iPhone models to sport larger RAM capacities.
But Qualcomm senior vice president and chief marketing officer Anand Chandrasekher says Apple's use of a 64-bit chip is merely a gimmick. He points out that the main benefit of 64-bit technology is the increased RAM as previously mentioned, and isn't relevant with today's smartphones that have an average 1 GB of RAM. Heck, Samsung just started producing 3 GB LPDDR3 mobile memory back in July.
"Predominantly, you need it for memory addressability beyond 4 GB," he told Techworld in an interview. "That's it. You don't really need it for performance, and the kinds of applications that 64-bit get used in mostly are large, server-class applications."
Apple claims that the new iPhone 5S, which only has 1 GB of RAM, is two times faster than the original iPhone 5, and that the 64-bit chip brings desktop-style computing to the smartphone form factor. However, benchmark tests have reportedly led to questions about how much of the performance gains are actually due to the 64-bit chip. Naturally, to take full advantage of the new architecture, developers will need to upgrade their iOS apps.
The move to ARM's A64 architecture supposedly brings performance gains to the new phone thanks to an increase in the number of general purpose registers, double the number of FP/NEON registers (not to mention larger 128-bit registers for improved Single Instruction Multiple Data performance), and new cryptographic instructions for hardware acceleration.
The first batch of Apple's A7 chip was reportedly manufactured by Samsung on a high-κ metal gate (HKMG) 28 nm process. However, Apple is reportedly planning on using TSMC to produce 60 percent of the chips to be used in the iPhone 6. Meanwhile, Samsung said it's in the final stages of developing its own 64-bit Exynos chip for upcoming phones. Qualcomm is working on its own 64-bit chip as well.
"From an engineering efficiency standpoint it just makes sense to go do that. Particularly the OS guys will want it at some point in time," said Chandrasekher.