Performance degraded after upgrading VM from Standard_B4ms to Standard_B8ms

Hello @Sanjay

To resolve this, review the virtual machine's performance metrics, ensure adequate resources and storage types are configured, and check for any specific VM settings or hypervisor limitations that could be causing the issue. In the long term, evaluate whether a D-series VM is more appropriate for the workload's sustained CPU requirements.

• B-series VMs are designed for burstable workloads and rely on a credit system.
• Resizing a B-series VM can lead to performance degradation if the VM starts with a low credit balance.
• The fastest way to restore performance is to reduce CPU load and allow the VM to accumulate credits.
• For sustained high CPU usage, consider migrating to a D-series VM.

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Hello @Sanjay ,

Thanks for reaching out to Microsoft Q&A.
Looks like you are having performance issues after upgrading your Azure VM from Standard_B4ms to Standard_B8ms.

In the Azure Portal, monitor the "CPU Credits Remaining" metric.

If credits are low, the VM is throttled to baseline performance, causing slow system response.

• The fastest way to restore performance is to reduce CPU load and allow the VM to accumulate credits.
• Stop unnecessary background processes and let the VM idle as much as possible until credits rebuild.
• For workloads needing persistent, high CPU usage, consider migrating to a D-series VM.
• D-series VMs offer consistent performance and do not use a credit system—perfect for sustained workloads.
• Run PerfInsights to diagnose bottlenecks in CPU, disk, or memory, and confirm if it’s a credit limitation or another resource issue.
• If you use standard HDDs, upgrade to SSD-backed storage for better overall I/O performance.
• Use Azure Monitor to keep track of CPU credits and performance metrics.
• Set alerts to warn if CPU credits are running low, preventing unexpected slowdowns.
• Resizing a B-series VM can lead to performance degradation if the VM starts with a low credit balance. This often happens after a resize or restart, as credits may not transfer fully or replenish instantly.

Kindly let us know if the above helps or you need further assistance on this issue. Additionally reached for more details via private messages

Regards

Manish

Hello @Sanjay, If the Answer is helpful, please click Accept Answer and Up-Vote, so that it can help others in the community looking for help on similar topics.

Hello Sanjay.

I just wanted to kindly follow up to check if you had a chance to review my earlier response. I hope the information shared was helpful. Please feel free to reach out if you have any additional questions or need further clarification.

my question is same machine which had 16 GB ram was working good and when i upgraded that to 32 GB ram it slow down, can you help and schedule a call?