I have lenovo y580 with gtx660m optimus. gpu-z says my dgpu is running at 135/202 clocks during idle. sometimes it spikes to 835/1250 for no reason during idle. It appears that it is still running during idle. I have set default behavior in nvidia control panel to use the intel igp, but dgpu still runs. I want to turn it off during idle/low load without using the bios. How ?