Azure Cobalt 100 ARM Instances Now GA — Microsoft Custom Silicon Delivers 50% Better Price-Performance Than Intel D-Series

What is Azure Cobalt 100?

Azure Cobalt 100 is Microsoft's first custom ARM processor, based on the Arm Neoverse N2 architecture. Unlike third-party ARM chips used by cloud providers (such as AWS Graviton or Ampere Altra), Cobalt 100 is designed and optimised specifically for Azure's infrastructure and the workloads Microsoft's customers run most frequently. It is available in Dcas_v6 (general purpose) and Ecas_v6 (memory optimised) instance families.

What Changed?

Dcas_v6 and Ecas_v6 instances powered by Cobalt 100 are now generally available in all Azure regions including Singapore, West Europe, East US, and UK South. Pricing: Dcas_v6 starts at $0.077/hr for 2 vCPU/4GB RAM — 20% lower than the equivalent Intel Dsv5 at $0.096/hr. The instances support Premium SSD v2, accelerated networking up to 200 Gbps, and ultra-low latency NVMe local storage on the larger sizes.

Why Does This Matter?

The combination of 20% lower pricing and 40% better CPU performance vs Intel Dsv5 means Cobalt 100 delivers approximately 50% better total price-performance. For an 8-node Kubernetes cluster running 24/7, switching from D8s_v5 (Intel) to Dcas_v6 (Cobalt 100) saves approximately $720/month while processing 40% more requests — the effective saving in terms of work done per dollar is closer to 65%. Compared to Ampere Altra-based Dpsv5 instances, Cobalt 100 still delivers a 15% performance improvement.

How to Use It

Cobalt 100 runs Linux only — Windows Server is not supported on ARM architecture. For containerised workloads, most modern Docker images ship multi-architecture builds including ARM64. Verify your images by running: docker manifest inspect [image] | grep arm64. Key images with confirmed ARM64 support: nginx, postgres, redis, node, python, golang, java (adoptopenjdk), and most language runtimes. For AKS, create a Cobalt 100 node pool by selecting Dcas_v6 as the VM size — your existing Kubernetes workloads migrate without application changes.

Who Should Act Now

All teams running containerised Linux workloads on Azure should evaluate Cobalt 100. Priority targets: Kubernetes node pools running stateless services, API gateway nodes, web servers, message queue processors, and CI/CD build agents. Start by adding a Cobalt 100 node pool to your AKS cluster alongside existing Intel nodes, then gradually shift workloads using node selectors and taints while monitoring performance.