This document describes the possible impact on the performance and user density of a VDI environment when the system implements mitigations for Spectre, Meltdown, and L1 Terminal Fault (L1TF), or Foreshadow. Further analysis also provides insight on performance differences between Windows 10 versions (1709 and 1803) and hypervisors (ESXi and AHV). We expect customer results to vary, because a Login VSI workload is never the same as a real user workload. These results give an indication of the impact of upgrading from Windows 10 version 1709 to version 1803; changing the workload changes the outcomes.
Because Windows 10 is not designed to run as a virtual desktop on a server sharing CPU cycles with other Windows 10 desktops, you need to optimize it to make sure that it doesn’t use CPU, memory, and IOPS unnecessarily. For example, if Windows 10 in a VDI environment is not optimized, it runs scheduled tasks like disk defragmentation, scans the system for malware, installs Windows updates, and runs unnecessary services. These extra tasks create a bad user experience (slow applications, screen buildup) and reduce user density (because of the higher CPU load on the servers).
There are multiple tools and guides available to help you optimize a Windows 10 VDI image. A good general rule is to check each optimization carefully to see if it should be applied in your specific environment, rather than apply all the optimizations. Some optimizations can impact the functionality of applications.
Tools for Optimization
The following tools can help you optimize Windows 10 (External links - Disclaimer):
Vmware OS Optimization Tool (unsupported fling)
All three tools are valid for whichever type of VDI software (VMware, Citrix, Microsoft) you are using.
Documentation for Optimization
The following Windows 10 optimization guides are available (External links - Disclaimer):
The main areas in which you can optimize a Windows 10 VDI image are:
The new features in Windows 10 related to reporting and telemetry have garnered the most discussion. When Windows 10 is used in a VDI environment, these features negatively affect performance, while providing only minimal gains for user experience.
Tip: Disabling new reporting features such as boot logging and call home, as well as features related to telemetry, improves security and user density.
Any default Windows client operating system schedules tasks by default. While these scheduled tasks are useful and have little effect on physical deployments, they can have a significant effect on your VDI image. The Windows Automatic Maintenance feature, for example, scans your Windows OS whenever the machine is idle to check for errors, defragment the hard drive, and run optimization services. Running this task on hundreds or thousands of desktops in a centralized environment negatively affects your system’s active users. Other scheduled tasks magnify this effect.
Tip: When implementing VDI, disable scheduled tasks whenever possible, including defragmentation, automatic maintenance, and Bluetooth scanning.
When Windows 10 is hosted on one or more datacenters, some of the default services that come with Windows 10 add little benefit. Other default services add limited value when desktops are virtualized rather than deployed on PCs or laptops. Services like BranchCache, Internet Connection Sharing, and geolocation don’t add value when VDI software delivers the desktop services from a central location.
Tip: Disabling unused services hardens your OS and lowers OS overhead, which improves user experience.
The Windows 10 default deployment includes a list of preinstalled applications, many of which are consumer-focused, such as Twitter, Asphalt 8, Airborn, and FarmVille 2.
Tip: Removing consumer-focused apps frees up machine resources and limits end-user distraction.
Microsoft OneDrive is a file synchronization solution that allows you to connect to your Office 365 account (for example) and store your files both locally and in the cloud. OneDrive, however, is not built for virtualized desktops because it syncs all OneDrive content locally. If your VDI deployment contains nonpersistent desktops, OneDrive syncs the complete folder per user after every new logon to the system.
Tip: Uninstalling Microsoft OneDrive avoids wasting disk capacity and eliminates the network congestion caused by user folder synchronization actions.
Since the release of Microsoft Office 2013, Office has used a hardware-accelerated method for presenting Office programs such as Word and Excel. The Microsoft OS offers this feature, but the OS itself relies on the graphics processing unit (GPU) and the display drivers. If there is no GPU available, the CPU performs the rendering, which uses additional system resources.
Tip: If you have no GPU available, enable software rendering for Internet Explorer and disable hardware acceleration for Office 2010, Office 2013, and Office 2016 to improve user experience.
For more information, please visit our user guide.