I write here how I resolved my high cpu usage on my asus rog g752vy(i7 6700hq + 980m), maybe others need it:
I observed in idle that my cpu have 25-30% usage, this trigger the fan cooler to spin, and noise, I tried to find what software it is the culprit, the close I find was a system ACPI with a generic code.
After much of try and error, I find that if I go to bios/uefi(no need to modify or save something in bios, just to open/view), this high usage will start to happen after first reboot.
The only solution I found was to install/reinstall the Thunderbolt firmware from asus website, after this and reboot, poof the cpu usage in idle it is around 2-3% as it should be and the windows feel smoother.

Hope this help others too.