windows 8 64 bit, 4 gtx titans
Short description of error
Render with GPUs a single image, after rendering finished, GPU usage over does not go below 50 percent, whereas at idling it should be around 10 percent, apparently blender "does not" release them from their duties... Only when blender 3d is closed, GPU usage comes to normal 10 percent idling usage. All GPUs' usage is over 50 percent!!!
GPU usage before hitting f12 is around 10 percent! After hitting f12 - full stress - around 85 percent. After rendering finished over 50 percent! Closing blender 3d - 10 percent again.
Exact steps for others to reproduce the error
Based on a (as simple as possible) attached .blend file with minimum amount of steps