ARM Launches 64-bit Cortex-A50 Architecture, Coming To Cell Phones Through Servers In 2014
When AMD designed x86-64, its engineers took the opportunity to remove some cruft from the venerable IA-32 standard and cleaned up the implementation while maintaining backward compatibility. With ARMv8, ARM has done something similar. The ARMv7 uarch was designed to scale across three different markets with very different needs as far as power consumption and computation capability.
ARMv8 adds 64-bit memory addressing, increases the number of general purpose registers to 30, and increases the size of the vector registers for NEON/SIMD. In ARMv7, SIMD support was optional and the architecture specified 32 64-bit registers. ARMv8 retains the same 32 register configuration, but expands each register to handle 128-bit SIMD.
The Cortex-A57 and A-53 are both aimed at the mobile market. ARM describes the A57 as the fastest, most advanced single-threaded chip its ever built, claiming that it "Provides computer performance comparable to a legacy PC, while operating in a mobile power budget, enabling cost and power efficiency benefits for both enterprise users and consumers." The A-53 is described as the most power-efficient ARM chip, and is "optimized for throughput processing for modest per thread compute applications."
How much performance will ARM chips pick up thanks to this move? That's hard to predict. The move from 32-bit to 64-bit PCs was gradual and the performance gains were on the order of 10-15% depending on the application. One of the major differences between PCs and smartphones, however, is that 64-bit memory addressing was immediately useful for certain programs and applications. There weren't many people needing more than 4GB of RAM in a system back in 2003, but there were a few. ARM, in contrast, is attempting to break into these markets from scratch.
Partners that've already signed on to build ARMv8-based hardware include Samsung, AMD, Broadcom, Calxeda, and STMicro. Qualcomm and Nvidia are notable by their absence, but both companies are likely licensees at some point. We've talked before about the growing battle between Intel and various ARM licensees as Santa Clara pushes into mobile products, but this is the other half of that collision.
As ARM CPUs begin pushing into tablets and low-end laptops, Intel will face competitors it's never had to worry about before. It could be 18 months or more before the first Cortex-A53 and A57 CPUs ship, but you can bet Intel is making plans of its own to counter their advance.