Windows 10 Home 64Bit
CPU Intel i7 4770
GPU GeForce GTX 760 1,5 GB (192-bit) Driver Nvidia 372.90
Short description of error
Brightness of diffuse color per image based lightning is different on rendered image between cpu and gpu as render device. This behavior will shown with one of my HDR-Images. An other Image I have tested shown an equal brightness between cpu and gpu rendering of my scene.
Exact steps for others to reproduce the error
Open house-cycles3+hdr.blend and render once with cpu and second with gpu as device and switch between those two and have a look of the brightness of the plane.