The IDLE power consumption of Nvidia graphics cards in combination with a GSYNC monitor with a high refresh-rate is much higher compared to regular monitors. Nvidia confirmed the problem and is working on a solution.

During testing of a Asus PG279Q Ryan Shrout from PC Perspective discovered this abnormal behaviour. The 27"-in GSYNC monitor at 165 Hz made his test system use much more power in Idle opposed to your regular PC at a 60Hz refresh-rate. 

The power consumption differences in IDLE are massive, at 60 Hz the PC utilizes 74 Watts, yet at 165Hz his PC started using 201 Watts in IDLE, yes that's just displaying your idle Windows desktop.Once you look at the graphics card (in this case a GeForce GTX 980 Ti) the problem becomes abundantly clear, ay 60 Hz the card will have a baseclock of 135 MHz and with 120Hz or higher, the cards kicks in and remains at 885 MHz. The problem only seems to be focusing at GSYNC monitors. Disabling GSYNC does not change the power consumption at 144 Hz.

NVIDIA is looking into this and has found the problem. They will issue a fix with a driver future update.

Nvidia looking into problem high IDLE power usage vs high refreshrate