Linux Virtual Delivery Agent

HDX adaptive throughput

HDX adaptive throughput intelligently fine-tunes the peak throughput of ICA sessions by adjusting output buffers. The number of output buffers is initially set at a high value. This high value allows data to be transmitted to the client more quickly and efficiently, especially in high latency networks. This feature brings an enhanced user experience. It provides better interactivity, faster file transfers, smoother video playback, and higher framerate and resolution. Session interactivity is constantly measured to determine whether any data streams within an ICA session are adversely affecting interactivity. If that occurs, the throughput is decreased to reduce the impact of the large data stream on the session and allow interactivity to recover.


HDX adaptive throughput changes the way of setting output buffers by moving the mechanism from the client to the VDA. No manual configuration is necessary.

The feature requires the VDA minimum version 2311. It is disabled by default. To enable it, run the following command on the VDA:

/opt/Citrix/VDA/bin/ctxreg create -k "HKLM\System\CurrentControlSet\Control\Terminal Server\Wds\icawd" -t "REG_DWORD" -v "AdaptiveScalingEnabled" -d "0x00000001" --force

The feature applies to only the sessions that are launched after the feature is enabled.

HDX adaptive throughput