Product Documentation

GPU acceleration for Windows Desktop OS

Nov 04, 2016

With HDX 3D Pro you can deliver graphically intensive applications as part of hosted desktops or applications on Desktop OS machines. HDX 3D Pro supports physical host computers (including desktop, blade, and rack workstations) and XenServer VMs with GPU Passthrough and XenServer VMs with Virtual GPU (vGPU).

Using XenServer GPU Passthrough, you can create VMs with exclusive access to dedicated graphics processing hardware. You can install multiple GPUs on the hypervisor and assign VMs to each of these GPUs on a one-to-one basis.

Using XenServer vGPU, multiple virtual machines can directly access the graphics processing power of a single physical GPU. The true hardware GPU sharing provides desktops suitable for users with complex and demanding design requirements. Supported for NVIDIA GRID cards (see NVIDIA GRID), the GPU sharing uses the same NVIDIA graphics drivers that are deployed on non-virtualized operating systems. Also supported for 5th and 6th Generation Intel CPUs with Intel Iris Pro graphics. For more information on these families of Intel processors, see 5th Generation Intel Core Processors and 6th Generation Intel Core i5 Processors.

HDX 3D Pro offers the following features:

  • Adaptive H.264-based deep compression for optimal WAN and wireless performance. HDX 3D Pro uses CPU-based deep compression as the default compression technique for encoding. This provides optimal compression that dynamically adapts to network conditions.
  • Lossless compression option for specialized use cases. HDX 3D Pro also offers a CPU-based lossless codec to support applications where pixel-perfect graphics are required, such as medical imaging. Lossless compression is recommended only for specialized use cases because it consumes significantly more network and processing resources.
    When using lossless compression:
    • The lossless indicator, a system tray icon, notifies the user if the screen displayed is a lossy frame or a lossless frame. This helps when the Visual Quality policy setting specifies Build to lossless. The lossless indicator turns green when the frames sent are lossless.
    • The lossless switch enables the user to change to Always Lossless mode anytime within the session. To select or deselect Lossless anytime within a session, right-click the icon or use the shortcut ALT+SHIFT+1.

      For lossless compression: HDX 3D Pro uses the lossless codec for compression regardless of the codec selected through policy.

      For lossy compression: HDX 3D Pro uses the original codec, either the default or the one selected through policy.

      Lossless switch settings are not retained for subsequent sessions. To use lossless codec for every connection, select Always lossless in the Visual quality policy setting.

  • You can override the default shortcut, ALT+SHIFT+1, to select or deselect Lossless within a session. Configure a new registry setting at HKLM\SOFTWARE\Citrix\HDX3D\LLIndicator.
    • Name: HKLM_HotKey, Type: String
    • The format to configure a shortcut combination is C=0|1, A=0|1, S=0|1, W=0|1, K=val. Keys must be comma "," separated. The order of the keys does not matter.
    • A, C, S, W and K are keys, where C=Control, A=ALT, S=SHIFT, W=Win, and K=a valid key. Allowed values for K are 0-9, a-z, and any virtual key code. For more information on virtual key codes, see Virtual-Key Codes on MSDN.
    • For example:
      • For F10, set K=0x79
      • For Ctrl + F10, set C=1, K=0x79
      • For Alt + A, set A=1, K=a or A=1, K=A or K=A, A=1
      • For Ctrl + Alt + 5, set C=1, A=1, K=5 or A=1, K=5, C=1
      • For Ctrl + Shift + F5, set A=1, S=1, K=0x74

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. 

  • Multiple and high resolution monitor support. For desktop OS machines, HDX 3D Pro supports user devices with up to four monitors. Users can arrange their monitors in any configuration and can mix monitors with different resolutions and orientations. The number of monitors is limited by the capabilities of the host computer GPU, the user device, and the available bandwidth. HDX 3D Pro supports all monitor resolutions and is limited only by the capabilities of the GPU on the host computer.

    HDX 3D Pro also provides limited support for dual-monitor access to Windows XP desktops. For more information about this, see VDAs on machines running Windows XP or Windows Vista.

  • Dynamic resolution. You can resize the virtual desktop or application window to any resolution. Note: The only supported method to change the resolution is by resizing the VDA session window. Changing resolution from within the VDA session (using Control Panel > Appearance and Personalization > Display > Screen Resolution) is not supported.
  • Support for NVIDIA GRID architecture. HDX 3D Pro supports NVIDIA GRID cards (see NVIDIA GRID) for GPU passthrough and GPU sharing. NVIDIA GRID vGPU enables multiple VMs to have simultaneous, direct access to a single physical GPU, using the same NVIDIA graphics drivers that are deployed on non-virtualized operating systems.
  • Support for VMware vSphere and VMware ESX using Virtual Direct Graphics Acceleration (vDGA) - You can use HDX 3D Pro with vDGA for both RDS and VDI workloads.
  • Support for Microsoft HyperV using Discrete Device Assignment in Windows Server 2016.
  • Support for Data Center Graphics with Intel Xeon Processor E3 Family. HDX 3D Pro supports multi-monitors (up to 3), console blanking, custom resolution, and high frame-rate with the supported family of Intel processors. For more information, see and
  • Access to a high-performance video encoder for NVIDIA GPUs. This feature is controlled by a policy setting (enabled by default) and allows the use of hardware encoding for H.264 encoding (where available). If such hardware is not available, the VDA will fall back to CPU-based encoding using the software video codec.
    • Requires a VDA configured for HDX 3D Pro with an NVIDIA GPU that supports NVENC hardware encoding. See NVIDIA video codec SDK for a list of supported GPUs.
    • This feature is enabled by default with HDX 3D Pro.
    • NVIDIA GRID requires driver version 3.1 or higher. NVIDIA Quadro requires driver version 362.56 or higher. Citrix recommends drivers from the NVIDIA Release R361 branch.
    • Any Citrix Receiver that supports H.264 decoding can be used with NVENC hardware encoding.
    • Lossless text, a feature of the VDA when configured in standard mode (not HDX 3D Pro), is not compatible with NVENC hardware encoding. If it has been enabled in HDX 3D Pro mode, lossless text takes priority over NVENC hardware encoding.
    • NVENC hardware encoding supports both lossy (4:2:0) and visually lossless (4:4:4) compression. Visually lossless (graphics policy setting, Allow visually lossless compression) requires Receiver for Windows 4.5.
    • This feature performs full-screen H.264 encoding. Multiple monitors are supported. Selective use of the H.264 hardware codec for actively changing regions is not supported.
    • For more information, see Use hardware encoding for video codec in the Graphics policy settings article. 

As shown in the following figure:

  • The host computer must reside within the same Active Directory domain as the Delivery Controller.
  • When a user logs on to Citrix Receiver and accesses the virtual application or desktop, the Controller authenticates the user and contacts the VDA for HDX 3D Pro to broker a connection to the computer hosting the graphical application.

The VDA for HDX 3D Pro uses the appropriate hardware on the host to compress views of the complete desktop or of just the graphical application.

  • The desktop or application views and the user interactions with them are transmitted between the host computer and the user device through a direct HDX connection between Citrix Receiver and the VDA for HDX 3D Pro.

Diagram showing integration of HDX 3D Pro with XenDesktop and related components

Install the VDA for HDX 3D Pro

When you use the installer's graphical interface to install a VDA for Windows Desktop OS, simply select Yes on the HDX 3D Pro page. When using the command line interface, include the /enable_hdx_3d_pro option with the XenDesktop VdaSetup.exe command.

To upgrade HDX 3D Pro, uninstall both the separate HDX 3D for Professional Graphics component and the VDA before installing the VDA for HDX 3D Pro. Similarly, to switch from the standard VDA for Windows Desktop OS to the HDX 3D Pro VDA, uninstall the standard VDA and then install the VDA for HDX 3D Pro.

Standard VDA

VDA for HDX 3D Pro

Generally best for virtual desktops without graphics hardware acceleration, and for Remote PC Access.

Generally best for data center desktops with graphics hardware acceleration, unless more than four monitors are required.

Any GPU can be used for Remote PC Access, with some app compatibility limitations:

  • On Windows 7, 8, and 8.1, GPU acceleration for DirectX feature levels up to 9.3. Some DirectX 10, 11, 12 applications may not run if they do not tolerate fallback to DirectX 9.
  • On Windows 10, GPU acceleration is provided for windowed DirectX 10, 11, and 12 apps. DX 9 apps are rendered by WARP. DX apps cannot be used in full-screen mode.
  • OpenGL application acceleration in remote sessions if supported by the GPU vendor (currently only NVIDIA).

Supports GPU acceleration with any GPU, however console blanking, non-standard screen resolutions and true multi-monitor support require NVIDIA GRID or Intel Iris Pro graphics.

Leverages graphics vendor's driver for broadest application compatibility:

  • All 3D APIs (DirectX or OpenGL) that the GPU supports.
  • Full-screen 3D app support with Intel Iris Pro (Win10 only) and NVIDIA GRID.
  • Support for custom driver extensions and APIs. For example, CUDA or OpenCL.

Arbitrary monitor resolutions (limit determined by Windows OS and performance) and up to eight monitors.

Supports up to four monitors.


H.264 hardware encoding available with NVIDIA cards.

Install and upgrade NVIDIA drivers

The NVIDIA GRID API provides direct access to the frame buffer of the GPU, providing the fastest possible frame rate for a smooth and interactive user experience. If you install NVIDIA drivers before you install a VDA with HDX 3D Pro, NVIDIA GRID is enabled by default.

To enable NVIDIA GRID on a VM, disable Microsoft Basic Display Adapter from the Device Manager. Run the following command and then restart the VDA: Montereyenable.exe -enable -noreset

If you install NVIDIA drivers after you install a VDA with HDX 3D Pro, NVIDIA GRID is disabled. Enable NVIDIA GRID by using the Montereyenable tool provided by NVIDIA.

To disable NVIDIA GRID, run the following command and then restart the VDA: Montereyenable.exe -disable -noreset

Install Intel drivers

This step is only required if you install Intel drivers after you install a VDA with HDX 3D Pro or if the Intel driver has been updated.

In order to enable the Intel drivers required for multi-monitor support, run the following command using the GfxDisplayTool.exe, then restart the VDA: GfxDisplayTool.exe -vd enable

GfxDisplayTool.exe is included with the VDA installer. The GfxDisplayTool.exe is in C:\Program Files\Citrix\ICAServices.


Uninstalling NVIDIA or Intel drivers within ICA sessions is not supported.

Optimize the HDX 3D Pro user experience

To use HDX 3D Pro with multiple monitors, ensure that the host computer is configured with at least as many monitors as are attached to user devices. The monitors attached to the host computer can be either physical or virtual.

Do not attach a monitor (either physical or virtual) to a host computer while a user is connected to the virtual desktop or application providing the graphical application. Doing so can cause instability for the duration of a user's session.

Let your users know that changes to the desktop resolution (by them or an application) are not supported while a graphical application session is running. After closing the application session, a user can change the resolution of the Desktop Viewer window in the Citrix Receiver - Desktop Viewer Preferences.

When multiple users share a connection with limited bandwidth (for example, at a branch office), Citrix recommends that you use the Overall session bandwidth limit policy setting to limit the bandwidth available to each user. This ensures that the available bandwidth does not fluctuate widely as users log on and off. Because HDX 3D Pro automatically adjusts to make use of all the available bandwidth, large variations in the available bandwidth over the course of user sessions can negatively impact performance. 

For example, if 20 users share a 60 Mbps connection, the bandwidth available to each user can vary between 3 Mbps and 60 Mbps, depending on the number of concurrent users. To optimize the user experience in this scenario, determine the bandwidth required per user at peak periods and limit users to this amount at all times.

For users of a 3D mouse, Citrix recommends that you increase the priority of the Generic USB Redirection virtual channel to 0. For information about changing the virtual channel priority, see CTX128190.