Configure multiple output scenario properly: If your Smode output windows overlap several display devices, use NVIDIA Mosaic.
Ensure that your Smode output window does not extend beyond your desktop coordinates or miss part of the full display size to take advantage of all Nvidia full-screen optimizations.
Enforce EDID on all displays on all GPUs: Ensure proper EDID settings for all display devices connected to all GPUs, including the one used for the desktop (UI).
Make sure EDIDs have only one resolution/frequency available to avoid issues with OS/driver selection.
Ensure all EDIDs have the same pixel clock at a 10-kilohertz precision on all display devices, including the one used for the desktop (UI).
Also, ensure that external video matrix devices use the same EDIDs.
File format and streaming
Does your hap files has been transcoded via Smode ? Try to reencode them directly in Smode
Does your hap files has been trancoded with a different machines ? It is recommended in some cases to encode the files in HAP with the playback server
Check the format: AppleProRes for large resolution can be too heavy. Use HAP or HAPQ codec instead.
CPU and HDD
Problem detected with generative or with video files ?
Are hap files placed on an external HDD or a HDD not enough fast ?
Windows Power mode
Check if the power mode in windows is in "Maximum Performance" or "High Performance"