Product Documentation


Jun 13, 2017
Citrix HDX includes a broad set of technologies that provide a high-definition user experience. 

At the device

HDX leverages the computing capacity of user devices to enhance and optimize the user experience. HDX technology ensures users receive a smooth, seamless experience with multimedia content in their virtual desktops or applications. Workspace control enables users to pause virtual desktops and applications and resume working from a different device at the point where they left off.

On the network

HDX incorporates advanced optimization and acceleration capabilities to deliver the best performance over any network, including low-bandwidth and high-latency WAN connections.

HDX features adapt to changes in the environment, balancing performance and bandwidth by applying the best technologies for each unique user scenario, whether the desktop or application is accessed locally on the corporate network or remotely from outside the corporate firewall.

In the datacenter

HDX leverages the processing power and scalability of servers to deliver advanced graphical performance, regardless of the capabilities of the client device.

HDX channel monitoring provided by Citrix Director displays the status of connected HDX channels on user devices.

HDX Insight, the integration of NetScaler Network Inspector and Performance Manager with Director, captures data about ICA traffic and provides a dashboard view of real-time and historical details such as client-side and server-side ICA session latency, bandwidth use of ICA channels, and the ICA round trip time value of each session.

To experience HDX capabilities from your virtual desktop:
  • See how Flash Redirection, one of three HDX multimedia redirection technologies, accelerates delivery of Adobe Flash multimedia content:
    1. Download Adobe Flash player ( and install it on both the virtual desktop and the user device.
    2. On the Desktop Viewer toolbar, click Preferences. In the Desktop Viewer Preferences dialog box, click the Flash tab and select Optimize content.
    3. To experience how Flash Redirection accelerates the delivery of Flash multimedia content to virtual desktops, view a video on your desktop from a web site containing Flash videos, such as YouTube. Flash Redirection is designed to be seamless so that users do not know when it is running. You can check to see whether Flash Redirection is being used by looking for a block of color that appears momentarily before the Flash player starts, or by right-clicking on the video and looking for Flash Redirection in the menu.
  • See how HDX delivers high definition audio:
    1. Configure your Citrix client for maximum audio quality; see the Citrix Receiver documentation for details.
    2. Play music files with a digital audio player (such as iTunes) on your desktop.
HDX provides a superior graphics and video experience for most users by default, with no configuration required. Citrix policy settings that provide the best out-of-the-box experience for the majority of use cases are enabled by default.
  • HDX automatically selects the best delivery method based on the client, platform, application, and network bandwidth, and then self-tunes based on changing conditions.
  • HDX optimizes the performance of 2D and 3D graphics and video.
  • HDX enables user devices to stream multimedia files directly from the source provider on the Internet or Intranet, rather than through the host server. If the requirements for this client-side content fetching are not met, media delivery falls back to server-side content fetching and multimedia redirection. In most cases, no adjustments to the multimedia redirection feature policies are needed.
  • HDX delivers rich server-rendered video content to virtual desktops when multimedia redirection is not available: View a video on a web site containing high definition videos, such as
Good to know:
  • For support and requirements information for HDX features, see the System requirements article. Except where otherwise noted, HDX features are available for supported Windows Server OS and Windows Desktop OS machines, plus Remote PC Access desktops.
  • This content describes how to further optimize the user experience, improve server scalability, or reduce bandwidth requirements. For information about working with Citrix policies and policy settings, see the Citrix policies documentation for this release.
  • For instructions that include working with the registry, use caution: editing the registry incorrectly can cause serious problems that may require you to reinstall your operating system. Citrix cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk. Be sure to back up the registry before you edit it.

Tablet mode for touch screen devices

By default, any touch enabled device that connects/roams to a Windows 10 VDA starts in tablet mode.

Tablet mode requires a minimum of version XenServer 7.2. XenServer 7.2 integrates with the XenDesktop VDA, changing the hypervisor to enable the virtual firmware settings for 2-in-1 devices. Windows 10 loads the GPIO driver on the target virtual machine based on this updated BIOS. It is used for toggling between tablet and desktop modes within the virtual machine. For .more information, see

The tablet mode offers a user interface that is better suited to touch screens:

  •  Slightly larger buttons.
  • The Start screen and any apps you start open in a full screen.
  • Taskbar contains a back button.
  •  Icons removed from the task bar.

You have access to the File Explorer.

Web Receivers do not support table mode.

localized image

Run the XenServer CLI command to allow laptop/tablet switching:

xe vm-param-set uuid=<VM_UUID> platform:acpi_laptop_slate=1

To disable (or re-enable) tablet mode, use the registry setting on XenApp and XenDesktop:


Editing the registry incorrectly can cause serious problems that may require you to reinstall your operating system. Citrix cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk. Be sure to back up the registry before you edit it.

To disable or enable the feature, configure this registry setting:

Name: CitrixEnhancedUserExperience

0 (Disable)
1 (Enable)

We recommend for the best results that you navigate to Settings >System >Tablet Mode before starting a session and set the following options from the drop-down menus:

  • Use the appropriate mode for my hardware
  • Don’t ask me and always switch 

If you don't set these options before starting the session, set the options after you start the session and restart the VDA.

localized image

Improve the image quality sent to user devices

The following visual display policy settings control the quality of images sent from virtual desktops to user devices.

  • Visual quality. Controls the visual quality of images displayed on the user device: medium, high, always lossless, build to lossless (default = medium). The actual video quality with the default setting of medium depends on available bandwidth.
  • Target frame rate. Specifies the maximum number of frames per second that are sent from the virtual desktop to the user device (default = 30). For devices with slower CPUs, specifying a lower value can improve the user experience. The maximum supported frame rate per second is 60.
  • Display memory limit. Specifies the maximum video buffer size for the session in kilobytes (default = 65536 KB). For connections requiring more color depth and higher resolution, increase the limit. You can calculate the maximum memory required.

Improve video conference performance

Several popular video conferencing applications have been optimized for delivery from XenApp and XenDesktop through multimedia redirection (see, for example, HDX RealTime Optimization Pack for Skype for Business). For applications which are not optimized, HDX webcam video compression improves bandwidth efficiency and latency tolerance for webcams during video conferencing in a session. This technology streams webcam traffic over a dedicated multimedia virtual channel; this uses significantly less bandwidth compared to the isochronous HDX Plug-n-Play USB redirection support, and works well over WAN connections.

Citrix Receiver users can override the default behavior by choosing the Desktop Viewer Mic & Webcam setting Don't use my microphone or webcam. To prevent users from switching from HDX webcam video compression, disable USB device redirection with the policy settings under ICA policy settings > USB Devices policy settings.

HDX webcam video compression requires that the following policy settings be enabled (all are enabled by default).

  • Client audio redirection
  • Client microphone redirection
  • Multimedia conferencing
  • Windows Media Redirection

If a webcam supports H.264 hardware encoding, HDX video compression uses the hardware encoding by default. Hardware encoding may consume more bandwidth than software encoding. To force software compression, add the following DWORD key value to the registry key: HKCU\Software\Citrix\HdxRealTime: DeepCompress_ForceSWEncode=1.