I also face the same problem with VIVE PRO EYE...
My development environment is 32 GB of ram, an i9, and RTX 2080 SUPER graphics.
In my case, a frame rate seems to get 60fps for first few seconds, however, then, it drops to 1 or lower fps.
The purpose of a dual camera is SRWorks. Because of this problem, sample applications provided by a SRWorks plugin and a camera test provided by a steemvr app are not worked well.