A deeper look at Cortex A50: 64-bit ARMv8 CPU cores running at up to 3GHz on phones and tablets in 2014
The Cortex A50 initally comes in two versions conveniently called LITTLE and big, technically represented by the Cortex A53 (LITTLE) and Cortex A57 (big). Both are based on the latest ARMv8 architecture that prioritizes power efficiency.
Unlike other companies, ARM is only designing the architecture while other companies like Apple, Qualcomm and so on build the actual chips. ARM expects the first Cortex A50 chips to launch at 28nm and 20nm manufacturing nodes, but it also plans to have them on 14nm in the future as well.
The big news obviously is that Cortex A50 brings 64-bit processing to the mobile space. Currently, Android and other mobile operating systems are 32-bit, and that means they can address as much as 4GB of memory. That is definitely not a problem in the mobile space right now (we barely have phones with 2GB of RAM), but desktop applications have long ago bumped into that limit for complex tasks in programs like say Photoshop, ArchiCAD, and so on. Having access to more than 4GB of RAM means that more intensive tasks can all be processed in the RAM. This move to 64-bit is not going to happen overnight in mobile, but ARM whips out the new design in anticipation of such a future.
The two variations of Cortex A50 target different goals. The “big” Cortex A57 aims for performance. It is similar to a Cortex A15 design having a 15-stage pipeline with a 3-wide instruction decoder. The A57 will run at clock speeds of up to 3GHz (depending on the chip manufacturer), and this will bring a noticeable 20% to 30% boost in speeds over Cortex A15.
The “LITTLE” Cortex A53 is similar to the Cortex A7, but again it adds 64-bit support. A53 is a much simpler architecture that focuses on power efficiency and performance-wise ARM promises it would match current A9-based systems. Clock speeds are expected to max out at around 1.3GHz. However, at current 32nm manufacturing it would take up only 60% of A9’s space.
As you’d expect, “big” and “LITTLE” could be combined in various big.LITTLE configurations allowing for the more power efficient LITTLE core to take over when you are doing simple taks like navigating the UI, and the big core would kick in when you start playing games for example.
Overall, this is the reassuring and logical next step for ARM, building up on the current strategy of using Cortex A15 for the high-end and Cortex A7 for the low-end. With Intel getting that second-gen Atom core ready soon, it will be pretty exciting watching the mobile chip race in the next couple of years.
source: AnandTech, GigaOM