ARM Announces Cortex-A76 and Cortex-X1 CPUs, and Mali-G78 and Mali-G68 GPU for Next-Gen Smartphones

BY Asif Shaik

Published 26 May 2020

ARM Cortex-A78 Cortex-X1 CPU

Android smartphones have been lagging in terms of raw performance compared to iPhones ever since Apple switched to 64-bit CPU with the iPhone 5s. However, that could change next year. Today, ARM unveiled two new CPUs—Cortex-A78 and Cortex-X1—and two new GPUs: Mali-G68 and Mali-G78. These CPUs and GPUs would appear in Android smartphones starting next year.

All Android smartphones, smartwatches, smart TVs, and tablets use processors that are based on ARM’s microarchitectures and CPUs. Even Apple uses ARM’s architecture to design processors for iPhones and iPad, but the company uses heavily modified designs rather than using stock ARM CPUs. As a result, Apple’s mobile devices are usually two years ahead in terms of performance when compared to similarly-priced Android devices.

Today, during its TechDay announcement, ARM has unveiled two new CPUs and two new GPUs. While the Cortex-A78 CPU offers an iterative improvement over last year’s Cortex-A77, the Cortex-X1 CPU provides a generational leap and could help plug the performance gap between Android and iOS smartphones. Let us have a look at the features and performance claims of Cortex-A78 and Cortex-X1 CPUs, as well as Mali-G68 and Mali-G78 GPUs.

ARM Cortex-A78 CPU: Iterative Performance

ARM Cortex A78 CPU

The Cortex-A78 CPU, which first appeared in ARM’s product roadmap two years ago under the codename ‘Hercules,’ is an evolution of the Cortex-A77. It is the third iteration of the company’s Austin CPU design. The company has designed Cortex-A78 with a focus on offering “high-end performance at the best efficiency” in terms of power and space.

Cortex-A78 claims to offer a 20% jump in terms of sustained performance over Cortex-A77. The performance improvement comes as a combination of both design improvement and the 5nm fabrication process. The company said that its goal was to offer reasonable performance improvements with reduced power consumption and a reduction in size. ARM is still using the ARM v8.2 architecture and shares the ISA compatibility with Cortex-A55 CPU cores.

ARM claims that Cortex-A78 cores are up to 50 percent more power-efficient when compared to Cortex-A77 cores while performing similar tasks. It also takes up 5 percent less physical die size when compared to Cortex-A77. We expect to see Cortex-A78 CPU cores in a lot of mid-range and high-end smartphones over the next few years.

ARM Cortex-X1 CPU: A Generational Leap In Performance Over Cortex-A77, Cortex-A78

ARM Cortex-X1 CPU

The Cortex-X1 is the first CPU in the company’s new lineup of flagship processors. With the new lineup, the company is focusing on absolute performance rather than taking a balanced approach. It has a 5-wide decoder compared to Cortex-A78’s 4-wide decoder. Its bandwidth is also wider, at 8Mops/cycle, when compared to Cortex-A78’s 6Mops/cycle bandwidth.

Cortex-X1 has four 128-bit NEON units, 64kB L1 cache, up to 1MB L2 cache, and up to 8MB L3 cache. In comparison, Cortex-A78 has two 128-bit NEON units, 32kB (or 64kB) L1 cache, up to 512kB L2 cache, and up to 4MB L3 cache. Overall, the Cortex-X1 has the same building blocks as that of Cortex-A78, but it uses larger and broader units. You can think of the Cortex-X1 as the Cortex-A78 on steroids.

ARM Cortex-A78 Cortex-X1 CPU Performance Comparison

Compared to the Cortex-A77, the Cortex-X1 offers up to 30 percent higher integer performance and up to 100 percent higher performance in ML (machine learning) and AI (artificial intelligence) tasks. Compared to the Cortex-A78, ARM says that the Cortex-X1 offers up to 22 percent higher integer performance and 2x the performance in machine learning tasks.

Cortex-X1 is a result of the CXC program in which ARM makes custom CPU cores in collaboration with its partners. We expect to see one or two Cortex-X1 CPU cores in flagship smartphone processors. Going by ARM’s performance claims, processors that use Cortex-X1 CPU cores would be able to offer performance that’s in the same ballpark as that of Apple’s A13 Bionic SoC. However, by that time, Apple would’ve released the A14 chipset with even better performance.

ARM Mali-G78 & Mali-G68 GPUs

ARM Mali-G78 GPU

Last year, ARM had unveiled the Mali-G77 CPU based on a brand new ‘Valhall’ GPU. Today, the company announced an extension of the Mali-G77 GPU in the form of Mali-G78. The new GPU offers up to 25% higher graphics processing performance compared to Mali-G77 in specific scenarios.

Mali-G77 supports up to 24 GPU cores, which is 50% higher compared to Mali-G77. This should result in beefier GPUs in smartphones and tablets. Expect to see around 17% improvement in real-world performance in games, thanks to advancements in ARM’s GPU design and process node improvement.

The Mali-G68 is a GPU for entry-level and mid-range devices. It mostly has the same features as that of the Mali-G78 GPU but can scale to lower core counts (up to six) and lower clock speeds. Essentially, ARM is naming the GPU as Mali-G68 if it has six or lower cores, and as Mali-G78 if it has seven or more GPU cores.

We expect to see Mali-G78 and Mali-68 GPUs in smartphone processors from MediaTek, Samsung, and UNISOC.

ARM Mali-G78 GPU Performance And Power Efficiency

[Source: ARM]