Are you sure you're testing the exact same scene with the exact same settings?
What I can confirm is that with RTX enabled you won't get close to 100% load - that's simply due to the way RTX raytracing with Vulkan is currently integrated into the Enscape OpenGL renderer. As a simplification you could say that the GPU has to wait a small amount of time everytime when we switch from OpenGL to Vulkan for raytracing and then back to OpenGL - this synchronization also affects scheduling and therefore it's difficult to get close to 100% efficiency. That doesn't necessarily mean that the performance is worse though - when the raytracing tasks finish much faster than the synchronization overhead it's still a net win, also RTX allows much more geometry to be traced.
Another thing to consider, what kind of scene are you testing on? In the above screenshot it looks like there's mostly sky visible. That won't keep the GPU busy enough. For capturings there's added overhead due to GPU - CPU synchronization, so the GPU load will usually be lower than during walkthroughs (with Restmode disabled). We have in fact added some more synchronization for capturing to reduce driver time outs when rendering very high resolution images, this could affect GPU load, but won't be really noticeable when it comes to rendering times.
With a medium sized scene I can easily get a Quadro RTX 5000 to 99% GPU load on 1080p. With RTX enabled load is considerably lower.


We're currently busy on reducing the added Vulkan interop overhead, so in future versions the efficiency with RTX enabled will definitely improve.
Hope that clears up some of it 