Are Power Settings Holding Back Your Virtual Machines?

by | Aug 21, 2017 | Infrastructure | 0 comments

Physical servers continue to increase in processor socket and core count. This increase in resources has been a boon for performance, but it’s come at the expense of larger power draw. To reduce power consumption, many vendors have implemented power savings settings at the hardware level by controlling the processor P-States. As you may have guessed, this can have a negative effect on the performance of virtual machines running on that server. If you’re trying to get the best performance out of your virtualization hosts, this post can help. There is a common setting that is often overlooked on servers that are running virtual workloads – power plans in the BIOS.

Power Settings in the BIOS

By default, several hardware vendors are shipping servers that are configured with a Balanced power state. As an example, VMware recommends using the “Maximum Performance” or “Static High-Performance” modes.

VMware has published a technical support article on this very issue, “Virtual machine application runs slower than expected in ESXi.” For Hyper-V users, Microsoft makes a similar note in this blog post.

Leaving the physical host power settings at the default setting is one of the most common causes of performance issues.

Here are a couple of issues that we have seen in the field because of the default balanced power plans:

  • A Physical to Virtual (P2V) converted server ran much slower as a virtual guest on a newer physical host. In reality, the new host should have been much faster since the virtual hardware was several years newer, faster processor, memory, etc. When the physical server was configured to the High-Performance mode, the migrated server was performed as expected, and ran better than when it was a physical server.
  • A large call center application was taking minutes to initialize on a user’s PC. After configuring the physical server to the High-Performance mode, the application consistently loaded within seconds.

If you’re making an investment in on-premises servers, it’s important that you get the best performance that you can. Hopefully this tip helps you to maximize your resources.

If you have any other questions about getting the most out of your technology investments – whether on-premises or in the cloud – email We are happy to help.