ARM64 vs X64 – Everything you need to know

In the rapidly changing world of technology, choosing the right processor architecture can significantly affect performance, efficiency, and cost.

At RunCloud, we’ve witnessed the impact of CPU architecture choices, particularly in server environments where performance and efficiency directly affect business costs. While consumers might be exploring ARM processors for personal computing, our focus is on the server-side revolution: how different CPU architectures are affecting cloud infrastructure, application performance, and operational efficiency.

In this comprehensive RunCloud guide, we explore the differences between ARM and x86 architecture. Whether you’re looking to optimize your server fleet or understand the latest computing trends, we’ll provide the insights you need to make informed decisions.

From performance benchmarks to practical implications, we’ll break down everything you need to know about ARM and x86 architectures in the context of modern computing and cloud infrastructure.

Let’s get started!

What is CPU Architecture?

CPU architecture is the fundamental design and operational blueprint of a computer’s central processing unit. It defines how it processes, manages, and executes instructions at the most elemental hardware level. It dictates the core structural elements that determine how a processor:

• Interprets machine instructions
• Manages data flow
• Handles computational tasks
• Allocates and uses registers
• Manages memory interactions

To understand this, you can think of CPU architecture as the engine design in a car, software as the driver’s instructions, and the operating system as the dashboard and control mechanisms that coordinate everything.

How is CPU Architecture Different from Software?

Software operates as an abstract layer on top of the CPU architecture. It is basically a set of instructions translated into machine-level commands. It depends on the underlying architecture for execution and can be compiled or interpreted to match specific CPU instructions.

How is CPU Architecture Different From The Operating System?

Operating systems manage hardware resources and provide an interface between other software and the computer’s hardware. Through specialized kernels and drivers, an operating system can support multiple CPU architectures.

However, this is only possible if the developer creates a specialized version of the operating system for a particular architecture. For example, Windows has a special version of its operating system for Windows on ARM devices. 

Aspect	CPU Architecture	Software/OS
Level of Operation	Hardware-level	Logical/Functional level
Modification Complexity	Requires physical redesign	Can be updated/replaced easily
Dependence	Direct hardware capabilities	Dependent on an underlying architecture

ARM Server Architecture

ARM64 refers to the 64-bit ARM processor architecture, also known as ARMv8-A. It is a RISC (Reduced Instruction Set Computer) design that provides significant improvements over the previous 32-bit ARM architecture.

ARM64 processors are widely used in various devices, including smartphones, tablets, laptops, and servers. They are also used in nearly all modern mobile devices, where power efficiency is crucial. Although it still has some rough edges, ARM64 is gaining traction in the embedded system design and cloud computing domains, where its performance and scalability are valuable assets.

There are two primary reasons why people use the ARM CPUs:

1. Improved performance: Compared to 32-bit ARM processors, ARM64 processors have a more efficient instruction pipeline and can execute more instructions per clock cycle.
2. Power efficiency: The ARM64 architecture is designed for low power consumption, making it well-suited for mobile, embedded, and IoT (Internet of Things) applications.

X86 Server Architecture

The X64 architecture, also known as AMD64 or Intel 64, is a 64-bit extension of the x86 architecture. It was developed by AMD and later adopted by Intel to develop CPUs. Now, it has become the predominant 64-bit processor architecture for desktop and server computers.

X86 architecture was predominantly used in the early days of computing, but it was later replaced by X64 architecture for several reasons:

1. 64-bit registers and address space: X64 processors support 64-bit integer and floating-point data types, allowing them to access significantly more memory (up to 16 exabytes) compared to the 32-bit x86 architecture.
2. Expanded instruction set: X64 introduces additional instructions and registers that enhance performance for 64-bit applications. This includes support for more general-purpose registers, which can improve the efficiency of arithmetic and logical operations.
3. Backward compatibility: X64 processors maintain compatibility with the 32-bit x86 instruction set, ensuring that existing software designed for 32-bit systems can run seamlessly on 64-bit platforms.

ARM vs x64(x86) Server Architecture Comparison Guide

RunCloud supports both ARM and AMD64 CPU architecture for your servers, but if you are looking to pick between ARM and x86 architecture, then there are several things that you should know:

Core Architectural Comparison

The ARM and x86 architectures are two fundamentally different approaches to CPU design, primarily distinguished by their instruction set architectures (ISA).

• ARM follows a Reduced Instruction Set Computing (RISC) model, which is a simpler, more streamlined instruction that can be executed quickly and with lower power consumption.
• In contrast, x86 uses a Complex Instruction Set Computing (CISC) approach, which supports more complex, multi-step instructions that can perform sophisticated operations with fewer lines of code.

While these architectures cannot directly run each other’s machine-level code due to their distinct instruction sets, modern programming languages provide a critical abstraction layer. Compilers can translate high-level code into architecture-specific machine instructions, allowing the same source code to be compiled for both ARM and x86 processors.

This means a Python, Java, or C++ program can be compiled to generate native instructions specific to ARM or x86 architectures, enabling software portability across different CPU types while maintaining optimal performance for each platform.

Feature	ARM Architecture	x86 Architecture
Instruction Set	RISC (Reduced Instruction Set Computing)	CISC (Complex Instruction Set Computing)
Power Efficiency	Typically 30-50% better power efficiency	Higher power consumption but improving with newer generations
Cost Structure	Lower licensing costs, emerging ecosystem	Mature ecosystem, competitive pricing due to scale
Market Maturity	Growing rapidly, especially with AWS Graviton	Dominant market position, extensive vendor support

Software Compatibility

Software compatibility between ARM and x86 architectures has significantly improved, with most modern programming languages and frameworks offering native support for both platforms through cross-compilation techniques.

Major platforms such as Linux, Windows, and macOS now provide robust toolchains that enable developers to build applications that can be easily recompiled for different CPU architectures.

While some specialized software and low-level system utilities may still require architecture-specific modifications, the vast majority of high-level applications can now be seamlessly adapted between ARM and x86 with minimal additional engineering effort.

Software Type	ARM Support	x86 Support
Linux Distributions	Full support in major distros (Ubuntu, RHEL, etc.)	Universal support
Container Support	Native Docker support, growing ecosystem	Comprehensive support
Web Servers	nginx, Apache, Lighttpd	All web servers supported
Databases	MySQL, PostgreSQL, MongoDB	All major databases
Programming Languages	Most languages supported natively	Universal support

Cost Considerations

ARM-based server architecture is considered a cost-effective alternative to traditional x86 systems, primarily due to its inherently lower power consumption and more efficient chip design. The fundamental energy efficiency of ARM processors allows data centers to significantly reduce electricity costs.

This reduction in operational expenses is why major cloud providers and enterprise data centers are gradually shifting their infrastructure towards ARM-based solutions.

But the cost advantages extend beyond just power consumption.

ARM’s design allows for more compact and thermally efficient chip manufacturing, resulting in lower hardware production costs and the ability to create denser server configurations. This economic incentive is particularly compelling for hyperscale cloud providers and large-scale computing environments that operate thousands of servers simultaneously.

Factor	ARM	x86
Hardware Costs	Lower initial investment	Variable, competitive at scale
Operating Costs	Lower power consumption	Higher power costs
Support Costs	It may require specialized knowledge	Widely available expertise

Benchmarks: ARM vs x86 Server Performance

We designed a controlled testing environment that minimized variables and provided a fair assessment of ARM versus x86 server performance.

We deployed two identical server configurations within the same cloud provider and region, carefully matching specifications including vCPU count, memory allocation, and network parameters.

After that, we created a standard WordPress installation with 20 blog posts for our performance evaluation.

We used k6 for load testing and Grafana for performance visualization to execute a 5-minute load test with 20 concurrent virtual users. During our tests, we tracked critical performance metrics, including requests per second, response times, and HTTP failure rates.

Metric	ARM	x86
Requests Made	8.8k	5.7k
HTTP Failures	0	0
Peak Requests per Second (RPS)	32	21.67
P95 Response Time	383ms	893ms

The benchmark results show notable performance advantages for ARM-based servers in this specific test scenario. Key observations include:

1. Request Volume: ARM servers processed approximately 54% more requests compared to x86 servers, indicating a significant throughput improvement.
2. Request Efficiency: The peak requests per second for ARM servers (32 RPS) substantially outperform x86 servers (21.67 RPS), which shows enhanced computational efficiency.
3. Latency Performance: The P95 response time for ARM servers (383ms) is markedly lower than that for x86 servers (893ms), representing a dramatic reduction in latency that could improve user experience.

By maintaining strict control over testing variables and using industry-standard performance analysis tools, we created a transparent and reproducible benchmark methodology. Our goal was not to declare a definitive winner but to provide an objective, data-driven perspective on the current performance capabilities of ARM and x86 server architectures.

While these benchmarks highlight ARM’s impressive performance, it’s important to understand that server architecture selection is nuanced. x86 server architecture is a robust, mature technology with:

• Extensive ecosystem support
• Proven reliability
• Widespread enterprise adoption
• Significant ongoing development and optimization

The results should be interpreted as a demonstration of ARM’s emerging capabilities rather than a wholesale replacement recommendation. When considering architectural transitions, you should evaluate their specific workload requirements, existing infrastructure, compatibility needs, and total cost of ownership.

Final Thoughts: Navigating Server Architectures with Flexibility

Throughout this article, we have discussed the different nuances of ARM and x86 architectures, as well as each platform’s strengths and considerations.

However, the choice between ARM and x86 is no longer a binary decision but a strategic consideration dependent on specific workload requirements, cost structures, and performance needs.

If you manage a fleet of servers, balancing ARM and x86 environments can quickly become a logistical nightmare. Deployment, optimization, and consistent performance management across different server types demand significant technical expertise – RunCloud is designed to eliminate these complexities.

RunCloud provides comprehensive support for both ARM and x86 server environments. Whether you’re exploring performance optimizations or scaling your infrastructure, RunCloud ensures seamless deployment, monitoring, and control across different server architectures.

Learn more about how RunCloud can help you manage your servers.