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Today, we are excited to announce the public preview of VM Customization feature in Azure introducing two powerful new capabilities: Disable Simultaneous Multi-Threading (SMT/HT) and Constrained Cores. These features give customers unprecedented control over virtual CPU configurations, enabling performance optimization and significant software licensing savings across a wide range of workloads.

VM Customization is designed to meet the evolving needs of customers who require flexibility in how compute resources are allocated. Whether you’re optimizing cost, performance, or compliance, these features allow you to tailor VM configurations to match your licensed capacity, workload profile, or infrastructure strategy without compromising on memory, storage, or I/O.

This launch marks a major milestone in Azure’s commitment to customizable infrastructure. By decoupling core count from VM size, customers can now deploy high-memory or high-bandwidth VMs with fewer active cores, reducing software licensing costs and improving efficiency. Combined with the ability to disable hyperthreading for latency-sensitive workloads, VM Customization unlocks new scenarios for database optimization, HPC, analytics, and more.

What’s New

With VM Customization, customers can now:

• Disable Simultaneous Multi-Threading (SMT/HT Off): Configure supported VMs to run with one thread per core, giving workloads exclusive access to physical cores for improved performance and latency consistency.


• Select Custom vCPU Counts: Choose from a guided list of valid vCPU counts per VM size to match licensing rights or workload needs without changing memory, storage, or I/O capabilities.

Why It Matters

VM Customization is designed to resolve persistent customer challenges by offering greater flexibility in how virtual machines are configured. For performance-sensitive workloads such as high-performance computing or financial modeling, disabling hyperthreading allows for full-core isolation, which can significantly enhance performance.

For database workloads like SQL Server, Oracle, or SAP, VM Customization enables customers to select only the number of cores they require, while still benefiting from the memory and bandwidth of larger VM sizes. This targeted approach can lead to substantial reductions in licensing costs.

Additionally, VM Customization simplifies compliance and cost optimization, especially for organizations operating under Bring Your Own License (BYOL) models or per-core software agreements. By tailoring VM resources to precise needs, customers can better align their infrastructure with both technical and business requirements.

Join the Preview

VM Customization is now available today in public preview across select regions, including West Central US, North Europe, East Asia, and UK South.

VM Customization is available via Azure portal, ARM templates, Azure CLI and PowerShell. Only first-party OS images are supported, Marketplace images with third-party licensing are not supported.

To request access to the preview, please fill out the survey form here. We look forward to hearing from you.