Here are my reproduction steps:
-Open a New Blank Project in Cubase 9
-Open Vienna Ensemble Pro Server Interface Plugin in Cubase (VST3)
-ASIO Usages jumps to 75% sustained and realtime peak is red zone.
-Disable VEP and ASIO usage returns to 0.
This is without any samples loaded or the server running. The interface plugin is not connected to anything but still is causing Cubase to perform this way. Other plugins behave fine.
ASIO Guard is disabled, and changing these settings has no effect. RME HDSPe AIO is set to 512 buffer, 48KHz. LatencyMon shows no issues with DPC latency or driver conflicts.
VEP 6.0.16419 (September 27)
Thanks for your help!