When it comes to choosing the best Arm Cortex processor, there are a few key factors to consider. The Cortex range offers a variety of options optimized for different use cases, so the “best” Cortex core depends largely on the specific needs of your application. However, some cores stand out for their exceptional performance and efficiency.
The Cortex-A78 is one of Arm’s newest and most powerful application processor cores. Announced in 2020, the A78 delivers up to 20% better performance than the previous Cortex-A77 core. Key improvements include:
- Enhanced branch prediction and prefetching for better instruction throughput
- Larger out-of-order execution window for greater parallelism
- Dedicated integer pipeline for optimal compute performance
The A78 excels at demanding tasks like 4K video processing, gaming, ML inferencing, and more. Its excellent single-threaded performance also makes it ideal for mobile devices. Leading-edge 5nm implementations like the Snapdragon 888 demonstrate the A78’s strengths.
Designed specifically for premium devices, the Cortex-X2 (codenamed “Mero”) represents the pinnacle of Arm’s mobile CPU technology. Unveiled with the A78, X2 is the first “big” Arm core, leveraging high-performance microarchitecture to deliver desktop-level performance on mobile SoCs.
Key attributes of the X2 core include:
- Massive out-of-order execution engine
- Enormous op cache improves throughput
- Advanced branch prediction enhances efficiency
- High-bandwidth memory subsystem
The Cortex-X2 provides up to 30% better single-thread performance versus the A78. While not as power efficient, the X2 establishes a new bar for mobile CPU performance. It powers flagship chips like the Snapdragon 8 Gen 1.
The Cortex-A76 remains a versatile and competitive mid-range core two years after launch. Fabricated on the mature 7nm process, the A76 achieves the optimal blend of performance and efficiency.
Key features include:
- Out-of-order 8-wide decode and dispatch
- Enhanced branch predictor and larger caches
- High-efficiency 7nm design
While the A78 now leads in performance, the A76 offers the best balance of compute, power, and area. It continues to power many popular mid-range and upper mid-range SoCs like MediaTek’s Dimensity 1000.
The smallest Arm core, the Cortex-A55 powers the “efficiency” side of big.LITTLE designs across smartphones, tablets, and other devices. Known for its frugal power draw, the A55 is built to deliver solid performance at minimal area and energy cost.
Attributes of the A55 include:
- In-order 8-stage scalar pipeline
- Small physical footprint (~0.5mm2 on 7nm)
- Advanced clock gating and power control
While it lacks compute muscle, the area-efficient A55 excels at low-intensity tasks like UI, media playback, and background processing. Its low-power nature makes it an essential ingredient in heterogeneous mobile SoCs.
Cortex-A510 and A710
For mid-range applications, Arm’s upcoming Cortex-A510 little core and Cortex-A710 big core offer an intriguing balance of performance and efficiency. These next-gen 7nm designs are targeted at upper mid-range smartphones, Chromebooks, IoT devices, and more.
The A510 aims to deliver a 20% boost over the A55 within the same power envelope. And the A710 brings up to 10% higher single-threaded throughput versus the A76.
Together, A510 and A710 promise to raise the bar for mid-range computing. First silicon designs will arrive in late 2022.
Key Factors in Choosing a Cortex Core
So which is the “best” Cortex CPU? There’s no one-size-fits-all answer. But here are some key considerations when selecting a core:
- Performance requirements – Light, moderate or heavy computation? Budget cores like A55 work for light workloads. A77 and A78 are better for intensive tasks.
- Power efficiency needs – Is battery life a priority? Smaller in-order cores like A55 excel here. Big cores maximize performance.
- Area constraints – How much die space is available? Smaller cores like A55 require less area than high-end cores.
- Target process node – Leading-edge 5nm? Mature 7nm? Architectures are optimized per node.
- Price point – Premium or mid-range SoC? Budget cores may fit mid-range pricing.
Analyzing these factors in the context of your specific application allows you to select the most suitable CPU core(s) from Arm’s diverse Cortex-A family.
Customized Cortex Cores
Beyond off-the-shelf cores, Arm enables further customization through CoreLink technology. Partners can tweak caches, interconnects, accelerators, and more to tailor a Cortex CPU to their exact needs.
For example, Samsung’s Exynos M1 and M2 couple A55 cores with specialized logic for enhanced mobile ML. So even standard Cortex CPUs can be optimized for specific use cases.
Putting it All Together via big.LITTLE
Rather than using a single core type, the best solution is often a heterogeneous big.LITTLE configuration. This combines power-optimized little cores with high performance big cores.
The typical setup utilizes Cortex-A55 for efficiency and Cortex-A7x for compute power. big.LITTLE allows workloads to be dynamically shifted to the right cores at the right times to maximize performance and battery life.
For example, a flagship mobile SoC might employ:
- 4x Cortex-X2 for demanding tasks
- 3x Cortex-A78 for optimal compute when needed
- 4x Cortex-A55 for lightweight background work
Such a 4+3+4 big.LITTLE configuration delivers the best overall user experience over a wide variety of workloads. The heterogeneous approach recognizes that different types of cores excel at different tasks.
The Road Ahead for Arm CPUs
With over 150 billion Arm-based chips shipped to date, the Cortex family has become ubiquitous across mobile, embedded, and infrastructure applications. And next-generation cores like X2, A78, A710, and A510 will continue pushing boundaries of performance and efficiency.
Beyond silicon, Arm is also leading research into new materials like graphene nanosheets and more holistic chiplet-based architectures. These breakthroughs may one day enable ultra-efficient 1000-core CPUs!
But in the near term, expect current core IP to further evolve and be tailored to new processes like 4nm and 5nm. Major leaps in CPU performance, ML acceleration, security, and specialized functionality will arrive via Arm’s platform approach of integrating diverse compute engines onto a single SoC.
So while individual cores are critical, remember that modern Arm-based systems-on-chip now incorporate GPUs, NPUs, DSPs, ISPs, and dedicated acceleration to deliver expanded capabilities and experiences. The future remains bright for Arm CPUs as part of this heterogeneous compute universe.