Thanks for the reply,
led software let me select "system status" and set CPU load effect but seems not reading correctly the effective cpu load from windows (monitored with SDK example, the cpu load stay stuck at -1)
Audio equalizer mode reads correctly the audio signal and lights up the keyboard.
As additional information i encountered an error the first time i updated the firmware of the keyboard resulting in not any kind of illumination; reflashing went ok.
I was planning to flash previous firmware version but i can't find any firmware.