Hello there,
It seems that this may be related to an issue reported here: [Content removed]
One setting to try would be r.VT.PageFreeThreshold 15 (down from the 5.2 default of 60. 15 is the default in UE Main going forward.), though if it is the same issue, there may be API validation issues when running with -rhivalidation or -d3ddebug.
If the issue isn’t related to that issue, I’m not sure I can see the PIX captures, but they would be useful to diagnose the issue further.
Best regards,
Chris