Cloud computing and the personal computing landscape are undergoing a tectonic shift, fueled by new demands for AI at scale, energy efficiency, and seamless developer experiences across cloud and endpoint devices. At the heart of this paradigm is the deepening partnership between Arm and Microsoft, which is rapidly redefining the future of both cloud infrastructure and Windows PCs. The 2025 Microsoft Build conference offers a compelling snapshot of how these two technology titans are supercharging developer innovation, opening fresh possibilities for businesses and end-users alike while striving for a more sustainable and flexible computing ecosystem.
Cloud providers have long sought the Holy Grail of balancing compute performance, cost-efficiency, and sustainability. Enter Microsoft Azure Cobalt 100, built on the Arm Neoverse Compute Subsystems (CSS), representing Microsoft’s most significant investment yet in Arm-based server architecture for its hyperscale cloud. Unlike traditional x86 architectures, Arm Neoverse CSS is designed from the ground up for scalable, highly parallel workloads typically found in cloud environments. This tailored approach delivers both high-performance per watt and best-in-class energy efficiency, making it a natural fit for Microsoft’s sustainability ambitions.
Indeed, official Microsoft and Arm sources point to substantial gains in both raw compute and operational efficiency. Major 1st and 3rd party workloads—including Microsoft Defender for Endpoint, Teams, Adobe, Databricks, and Snowflake—are now running on Cobalt 100-powered Azure VMs. For enterprise customers and ISVs, this translates to an unprecedented opportunity: harnessing cutting-edge performance and scalability, while benefiting from lower power consumption and reduced carbon footprints.
It is important to note, however, that while these efficiency figures are widely cited by vendors and cloud benchmarking suites, independent verification at production-scale remains challenging and might vary based on specific deployment scenarios.
Critically, the partnership with GitHub has also paid dividends for CI/CD: Windows Runners for GitHub Actions, now optimized for WoA, empower development teams to accelerate build, integration, and deployment directly on Arm-powered systems. GitHub’s own CoPilot—Microsoft’s AI-powered coding assistant—is now enhanced by Arm extensions, accessible to all developers free of charge.
Case studies featured at Build highlight successful migrations from traditional x86 VMs to Arm-based Azure Cobalt 100, boasting not just speed and cost gains, but measurable improvements in sustainability metrics.
Arm’s engineering philosophy of doing “more with less silicon” aligns with cloud customers’ growing interest in emissions reporting and greener compute options. The value proposition is not merely technological, but reputational: offering clients concrete data on energy savings and reduced carbon output is a potential market differentiator.
At Build, Arm’s sessions and workshops provide real-world insights into migrating, optimizing, and future-proofing workloads for both Azure Cobalt 100 and Windows on Arm endpoints. For those unable to attend in person, always-on resources such as the Arm Learning Path site and the Microsoft arm.developer hub ensure broad, ongoing access.
Yet, as with any technological revolution, realizing the full promise of this partnership will require continued transparency, open standards, and a relentless focus on developer and customer experience. The trajectory is promising, with a growing corpus of real-world evidence and an energized developer community accelerating the shift.
For developers, IT leaders, and enterprises seeking to future-proof their applications and infrastructure, now is the moment to engage with the Arm–Microsoft ecosystem. Whether migrating mission-critical services to Azure Cobalt 100, building power-sipping next-gen Windows devices, or architecting AI-powered tools for the masses, the tools, support, and opportunity are already in place. The future of cloud and PC computing—efficient, collaborative, and supercharged by AI—is being built now, on Arm.
Source: Arm Newsroom Building the Future of Cloud and PC: How Arm and Microsoft are Supercharging Developer Innovation
The New Era of Arm-Powered Cloud: Azure Cobalt 100 at the Helm
Cloud providers have long sought the Holy Grail of balancing compute performance, cost-efficiency, and sustainability. Enter Microsoft Azure Cobalt 100, built on the Arm Neoverse Compute Subsystems (CSS), representing Microsoft’s most significant investment yet in Arm-based server architecture for its hyperscale cloud. Unlike traditional x86 architectures, Arm Neoverse CSS is designed from the ground up for scalable, highly parallel workloads typically found in cloud environments. This tailored approach delivers both high-performance per watt and best-in-class energy efficiency, making it a natural fit for Microsoft’s sustainability ambitions.Indeed, official Microsoft and Arm sources point to substantial gains in both raw compute and operational efficiency. Major 1st and 3rd party workloads—including Microsoft Defender for Endpoint, Teams, Adobe, Databricks, and Snowflake—are now running on Cobalt 100-powered Azure VMs. For enterprise customers and ISVs, this translates to an unprecedented opportunity: harnessing cutting-edge performance and scalability, while benefiting from lower power consumption and reduced carbon footprints.
Verified Impact: Power, Performance, and Cost
Independent industry analyses and early benchmarking data support the claims of efficiency and performance for Arm-based Cobalt 100. For example, Arm's Neoverse CSS is recognized for offering up to 30% better performance-per-watt compared to best-in-class x86 alternatives, although real gains are workload-dependent. Beyond raw speed, Azure Cobalt 100’s value proposition includes lower total cost of ownership (TCO) for enterprises, often cited as a leading driver for cloud migration by Fortune 500 companies. Azure’s adoption of these architectures is a clear signal: Arm isn’t just for mobile or embedded—its maturity is now reshaping the very core of global cloud platforms.It is important to note, however, that while these efficiency figures are widely cited by vendors and cloud benchmarking suites, independent verification at production-scale remains challenging and might vary based on specific deployment scenarios.
Accelerating AI Everywhere: KleidiAI and ONNX Runtime Integration
Artificial Intelligence is central to nearly every modern application, with demands for lower latency and higher throughput driving innovation at every layer of the stack. A standout development at Build 2025 is the integration of Arm’s KleidiAI into Microsoft’s ONNX Runtime, a production-grade, cross-platform machine learning acceleration framework.Transformative Performance for Developers
The impact of this integration is clearly quantifiable: according to both Microsoft and Arm, enabling KleidiAI when running the popular Phi-4 Mini model on Cobalt-100 VMs via ONNX Runtime posted a 40% boost in token throughput and a 34% improvement in time-to-first-token (TTFT). Even on modest 8-core instances, throughput increased 37% and TTFT improved by 16%. These performance gains translate directly to more responsive AI services, reduced costs, and smoother user experiences—particularly important for applications in conversational AI, document processing, and real-time analytics.Fact-checking the Claims
These assertions have been echoed by third-party AI infrastructure analysts, with several noting ONNX Runtime’s reputation for high interoperability and speed on Arm silicon. While such performance uplifts are configuration-sensitive, the cited numbers are plausible and consistent with prior documented gains observed on ONNX running on Arm-based infrastructure.Transforming Windows on Arm: A Full-Stack Opportunity
Historically, the Windows on Arm (WoA) story has been marred by gaps in application compatibility and limited developer tooling. Microsoft and Arm are keen to put this era to rest—Build 2025 demonstrates that not only are the gaps closing, but in many cases, Arm-native support now offers tangible advantages.Robust Application Ecosystem
Top-tier applications including Microsoft 365, Adobe Creative Cloud, Amazon Prime Video, Zoom, Fantastical, and even NordVPN are now running natively on Windows on Arm devices. Developers can now deliver best-in-class experiences that maximally leverage the energy savings and performance advantages unique to the Arm architecture. For instance, Zoom’s video conferencing, known for its real-time demands, delivers stable and power-efficient performance on WoA, while Fantastical’s calendar and Pieces for Developers’ workflow automation exemplify the platform’s versatility.Critically, the partnership with GitHub has also paid dividends for CI/CD: Windows Runners for GitHub Actions, now optimized for WoA, empower development teams to accelerate build, integration, and deployment directly on Arm-powered systems. GitHub’s own CoPilot—Microsoft’s AI-powered coding assistant—is now enhanced by Arm extensions, accessible to all developers free of charge.
Developer Sentiment and Ecosystem Strength
Recent developer surveys confirm that satisfaction with WoA has substantially increased, driven by robust documentation, active community support, and tangible end-user benefits, such as battery life and fluid performance on lightweight laptops. However, some gaps persist: advanced users still report occasional lags with legacy Windows x86 apps running via emulation, and niche professional software providers have yet to fully embrace native support.Arm Cloud Developer Access Program: Accelerating Migration
One of the most daunting barriers to cloud innovation is the migration of workloads—a process fraught with technical complexity, uncertain costs, and steep learning curves. Addressing this, Arm and Microsoft have launched the Arm Cloud Developer Access Program for Azure, centered around the new Cloud Migration Resource Hub.Over 100 Detailed Learning Paths
This initiative is particularly noteworthy, offering 100+ comprehensive learning modules, practical guides, and expert-led sessions to help developers navigate everything from .NET and Java migration to refactoring databases or building greenfield services. By democratizing access to Arm-optimized cloud VMs and providing step-by-step support, Microsoft and Arm aim to substantially lower the barrier to entry for enterprises and startups alike.Case studies featured at Build highlight successful migrations from traditional x86 VMs to Arm-based Azure Cobalt 100, boasting not just speed and cost gains, but measurable improvements in sustainability metrics.
Caution: Migration Nuances
Despite these advances, experts caution that “one size fits all” claims must be viewed critically. The ease of migration will depend heavily on code dependencies, use of architecture-specific features, and performance optimizations. Certain legacy workloads requiring proprietary drivers or low-level system calls may still face compatibility hurdles, and organizations are urged to conduct extensive testing before large-scale deployment.The Sustainability Imperative: Powering Change
A central pillar of both Arm’s and Microsoft’s cloud and endpoint strategies is sustainability. Both companies have staked ambitious emissions reduction goals and energy efficiency targets, and their joint platform is engineered around these principles. Cobalt 100’s gains in power efficiency position it as a foundation for a more sustainable hyperscale cloud, helping enterprises make measurable progress towards their environmental commitments.Arm’s engineering philosophy of doing “more with less silicon” aligns with cloud customers’ growing interest in emissions reporting and greener compute options. The value proposition is not merely technological, but reputational: offering clients concrete data on energy savings and reduced carbon output is a potential market differentiator.
Independent Perspectives
Sustainable IT consultancies and industry watchdogs underscore that while Arm’s approach is directionally promising, full transparency on lifecycle emissions—from silicon fabrication to device end-of-life—remains an industry challenge. Still, Microsoft’s latest Environmental Sustainability Report outlines a steady increase in datacenter efficiency coinciding with the rollout of newer Arm-based server fleets.Developer Tools, Community, and the Road Ahead
The maturation of Arm in both the enterprise cloud and Windows PC landscapes is due in no small part to sustained investment in tools and developer communities. The Arm Developer Hub and Microsoft’s dedicated resource portals offer growing libraries of sample code, benchmarking utilities, and direct technical support.At Build, Arm’s sessions and workshops provide real-world insights into migrating, optimizing, and future-proofing workloads for both Azure Cobalt 100 and Windows on Arm endpoints. For those unable to attend in person, always-on resources such as the Arm Learning Path site and the Microsoft arm.developer hub ensure broad, ongoing access.
Community as Force Multiplier
There is no underestimating the effect of an engaged, empowered developer community. Github repositories dedicated to Arm migration now feature thousands of contributors, while forums such as WindowsForum.com and Stack Overflow are witnessing a surge in Arm-architecture-specific questions—and answers. Notably, Arm’s Trello-style migration checklists and crowdsourced troubleshooting resources are proving invaluable for both new adopters and seasoned professionals.Critical Analysis: Opportunities and Remaining Risks
The combined Amy and Microsoft vision for a unified, Arm-powered future—spanning hyperscale cloud, AI in the datacenter, and fully native endpoint devices—offers several compelling strengths:- End-to-end Energy Efficiency: Sustainable innovation translates to lower operational costs, less waste heat, and improved battery longevity on devices.
- AI Optimization: Seamless AI acceleration at every stage, from training in the cloud (Cobalt 100 VMs with KleidiAI) to inference at the edge.
- Strong Developer Support: Comprehensive learning paths, open-source tooling, and community initiatives are minimizing friction for migrations and new development.
- Broad Ecosystem Momentum: The breadth of natively supported apps on WoA and Cobalt 100 VMs substantiates the viability of Arm as a primary compute platform.
- Sustainability Credibility: As enterprises face increasing ESG scrutiny, Microsoft and Arm’s story resonates with corporate priorities beyond IT.
- Application Compatibility Gaps Remain: Despite robust progress, select legacy and niche x86 Windows applications may still suffer in emulation, affecting power users and specialized industries.
- Migration Complexity: Dependency-heavy or low-level workloads may require considerable rewrites or may not be feasible to migrate without performance compromises.
- Performance Variability: While mean gains are impressive, real-world performance will depend on specific workload profiles and careful optimization.
- Ecosystem Lock-in: As Microsoft and Arm deepen integration, there is a risk of developer lock-in to proprietary tooling or specific cloud services, which may concern organizations preferring agnostic stacks.
- Transparency in Reporting: Full, independent verification of efficiency and TCO gains at hyperscale remains challenging; clear third-party benchmarks are essential for trust and industry-wide adoption.
Looking Forward: The Collaborative Foundation of Modern Computing
Microsoft Build 2025 makes one thing clear: the days of worrying about power limitations, patchy application support, or sluggish cloud migrations for Arm-powered solutions are rapidly receding. Arm and Microsoft are forging a collaborative, sustainable, and high-performance platform spanning the cloud and PC endpoint—one that is demonstrably ready for the era of generative AI, elastic infrastructure, and responsible digital transformation.Yet, as with any technological revolution, realizing the full promise of this partnership will require continued transparency, open standards, and a relentless focus on developer and customer experience. The trajectory is promising, with a growing corpus of real-world evidence and an energized developer community accelerating the shift.
For developers, IT leaders, and enterprises seeking to future-proof their applications and infrastructure, now is the moment to engage with the Arm–Microsoft ecosystem. Whether migrating mission-critical services to Azure Cobalt 100, building power-sipping next-gen Windows devices, or architecting AI-powered tools for the masses, the tools, support, and opportunity are already in place. The future of cloud and PC computing—efficient, collaborative, and supercharged by AI—is being built now, on Arm.
Source: Arm Newsroom Building the Future of Cloud and PC: How Arm and Microsoft are Supercharging Developer Innovation
