GPU VRAM on Max if i rotate my Character in Viewport

My character does not have any materials. When I look at it in the viewport, then the VRAM 915MB of jumps to 1115MB. When I rotate it, then the VRAM from 1115MB to 2030MB jumps. Sometimes the program crashes, because the maximum is reached. When I rotated it and then click compile, then the VRAM jumps to 900-1000MB.
When I insert the character in the world and 5 times, then jerks the viewport from the World Editor very strong, but when I click Save, then everything is back to normal.
I have no Problem with my Animal.

In Blender:
My Character has 5800 Tris and 3800 Faces.
My Animal has 890 Tris and 435 Faces.

In UE4 Mesh Viewport:
Character 11530 Triangles 6740 Vertices
Animal 7050 Triangles 4350 Vertices

Sry for my bad english

I have 2 Scene Capture Components 2D with 2 Render Targets. This stream my camera. If I delete it, my VRAM is stable.