In my case GPU-Z shows GPU Load, Memory Controller Load and Video Engine Load. I've retested with standard clocks:
Values for Idle/DirectCompute/OpenCL/FurMark:
GPU Core Clock 400/602/602/602
GPU Memory Clock 300/1107/1107/1107
GPU Shader Clock 800/1296/1296/1296
Fan Speed 40%/57%/75%/100% (100% - 3100 RPM)
GPU Load 0-2%/94-98%/96-98%/99%
Memory Controller Load 2%/18%/51%/70%
Video Engine Load 0%/0%/0%/0%
Furmark was in fullscreen 1680x1050, MSAA 16x. Reached 100% in just two minutes. Values for DC/OCL were taken about the end of test(no less than 10 minutes).
Fan speed is quite reliable source of gpu load by my observation. GPU temperature is not, because fan speed rises quite gradually, while temperature almost not. Anyway in FurMark temperature reached 89 C after some minutes and 100% fan speed, so this card don't have overheating problem.
I wondered what Video Engine was, then I supposed it was about video decoding acceleration and ran MPC HomeCinema
(with built-in H264 DXVA decoder) 1080p movie. Video Engine Load counter finally come to life and was 26-50%, depending on scene complexity.
With standard clock result values were D482.6/C704.8, pretty close to previous.
Then I downclocked card with RivaTuner. But setting GPU Core value to 300 MHz(half of original) made screen flash after I ran the test and I've set it to 2D default value, 400 MHz. Also I've lowered other values to minimum in RivaTuner.
Finally core/memory/shader clock - 400/555/861, test result is D310.0/C475.6.