Cortex-A75 (ARM core): what it is, how it works and what it does

The Cortex-A75 is a CPU core architecture designed by ARM Holdings, oriented toward high-performance workloads on mobile devices. It is positioned as the performance core within a heterogeneous topology, where it is paired with lower-power cores dedicated to background tasks.

Principles and architecture

As a core in ARM's Cortex-A family, the A75 is licensed to SoC manufacturers who integrate one or more cores of this architecture into their processors. Its primary role is to handle operations that demand greater compute capacity per cycle, such as video decoding, light graphics rendering, or execution of demanding applications.

According to specifications documented in mobile device datasheets, the Cortex-A75 typically operates at a clock frequency of 2.0 GHz and is grouped in a performance cluster (designated cluster_1 in specification nomenclature) containing two cores of this architecture.

Typical SoC configuration

Evidence from smartphone datasheets indicates a heterogeneous octa-core configuration:

• Performance cluster: 2 Cortex-A75 cores at 2.0 GHz.
• Efficiency cluster: 6 Cortex-A55 cores at 1.8 GHz.

This 2+6 arrangement allows the operating system to assign critical tasks to the A75 cores and delegate low-priority work to the A55 cores, optimising the balance between performance and power consumption.

Applications

The Cortex-A75 is present in processors for smartphones and tablets in the mid-to-high and high-end segments. Its presence is documented in mobile device specification databases (GSM Arena, GSMArena, Kalvo, PhoneDady), confirming its primary use in the mobile computing segment.

Scope and limitations

The Cortex-A75 is not a complete processor but a core architecture that must be integrated into an SoC alongside memory controllers, graphics units, modems, and other blocks. Its absolute performance depends on the clock frequency, cache hierarchy, and memory bandwidth that the SoC manufacturer chooses to implement around the cores.

Being coupled with efficiency cores (Cortex-A55), the design assumes that not all execution threads require the same level of power; workloads exceeding the capacity of the six efficiency cores scale up to the two A75 cores.

How to interpret its presence in a product

When the designation Cortex-A75 appears in a device's technical specification, the following can be concluded:

1. The SoC employs a heterogeneous topology (big.LITTLE / DynamIQ) with performance and efficiency cores.
2. The performance cluster consists of two cores at 2.0 GHz.
3. The device is aimed at a mid-to-high or high price range, given that the A75 is reserved for upper segments compared to older performance cores.

The mention of "2x 2.0 GHz Cortex-A75 & 6x 1.8 GHz Cortex-A55" in a specification unambiguously identifies the microarchitecture of the performance cluster and that of the efficiency cluster, allowing the device to be compared with others using the same or a different combination of ARM cores.

References in datasheets

The sources consulted (GSM Arena, GSMArena, Kalvo, PhoneDady) record the Cortex-A75 under the keys cpu_cluster_1_core_arch, cpu_cluster_1, and cpu_config, confirming its role as the core of the first cluster in mobile processor specification nomenclature.