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Measuring Parallels RAS Performance in Azure Virtual Desktop

Benny Tritsch Freek Berson 22 Jan 2024

Digital employee experience (DEX) is determined by the quality of an employee's touchpoints with the technology that helps them get their work done. Examples of such touchpoints include drive redirection and Easy Print technologies in virtual Windows desktops or remote applications. Both functionalities are natively available in Microsoft Remote Desktop Services or Azure Virtual Desktop, but do not always provide the expected response time. This means that users may not be happy with this aspect of DEX.

Parallels RAS aims to reduce waiting times until redirected drives and printers are available and thus improve the user experience. But how good are these add-on features? EUC Score provides a scientific method that allows you to compare native Remote Desktop Services (RDS) and Azure Virtual Desktop (AVD) functionality with Parallels RAS extensions.

Accelerated File Redirection

Drive Redirection allows access to files and folders located on the local device from within a remote Windows desktop and is a very common scenario. Parallels RAS provides an Accelerated File Redirection feature that significantly speeds up access to local files and folders based on a caching mechanism. In the EUC Score clip below, the native RDS and AVD drive redirection experience on the right side (red color) is compared with accessing RDS and AVD resources using Parallels RAS Accelerated File Redirection on the left side (yellow color).

Drive Redirection Comparison


The comparison shows a clear difference. The same locally redirected folder (C:\Windows\system32) takes over a minute to fully enumerate within the native RDS and AVD experience, where Parallels RAS with Accelerated File Redirection performs the same action in a second. When investigating the animated performance counter data as shown in the EUC Score clip below, you can also see differences in CPU and storage usage.

Drive Redirection Comparison


If Parallels RAS with Accelerated File Redirection is not installed (color coded in red), more CPU usage is needed when enumerating the local files and folders during the minute that it takes. Parallels RAS with Accelerated File Redirection (color coded in yellow) stops using the CPU at an earlier stage. This can also increase the user density in case of multi-user scenarios like Remote Desktop Services based on Windows Server or Azure Virtual Desktop based on Windows 11 Enterprise Multi-Session. Furthermore, Parallels RAS with Accelerated File Redirection also shows less CPU queue length and lower spikes in IOPS.

The test scenario in the clips above is based on the C:\Windows\system32 folder, but also applies to more common scenarios when accessing the my documents, downloads, or desktop folder on the local drive. More information on Accelerated File Redirection and other user experience enhancements that come with Parallels RAS can be found in this blog article published by Parallel's Freek Berson.

Universal Printing

Remote Desktop Easy Print is an RDS and AVD feature that enables the redirection of client-attached printers to remote user session. As a result, printing works as expected from a user's perspective. But there are a few downsides of the Easy Print functionality. You cannot dynamically update the default printer upon local change, there is no control of the redirected printers' naming convention, and you cannot launch a published application before redirected printers are ready. In addition, reconnecting to an existing (idle or disconnected) session with Easy Print takes a significant amount of time until the redirection of all local printers is reestablished and on top of that many 3rd party applications require printers to be available before they launch.

Parallels RAS Universal Printing overcomes all Easy Print issues described above. The comparison in the EUC Score clip below highlights the time it takes Parallels RAS Universal Printing to reconnect printers versus the time it takes native RDS/AVD Easy Print to do the same.

Print Redirection Comparison


The test result shows a huge difference. Parallels RAS Universal Printing reconnects eight printers in less than three seconds, whereas native RDS / AVD Easy Print takes 16 seconds. This makes Parallels RAS Universal Printing over five times faster. In addition, using Parallels RAS Universal Printing in RDS/AVD sessions significantly reduces the resource consumption on the session host. This results in less IOPS and disk read/write operations and lower CPU load, as you can see in the EUC Score clip below.

Print Redirection Comparison


What becomes obvious is that using Parallels RAS Universal Printing is not a tradeoff between speed and resources; it is, in fact, a win-win situation. It improves the overall user experience while also consuming fewer resources. In case of multi-session scenarios like Remote Desktop Services based on Windows Server or Azure Virtual Desktop based on Windows 11 Enterprise Multi-Session, allowing more user sessions per host.

Find more information about the enhancements provided by Parallels RAS Universal Printing in another great blog article published by Freek Berson and in his Youtube video.


Microsoft Remote Desktop Services and Azure Virtual Desktop provide great features out of the box, but there is always room for improvements of the digital employee experience. This article shows EUC Score benchmarking test results highlighting Parallels RAS extensions that reduce load times of redirected drives and printers in RDS and AVD user sessions.