Using a HybridPower-capable nForce motherboard, such as those based on nForce 780a or 790i chipsets, a GeForce GTX 200 GPU can be fully powered off when not performing intensive graphics operations and graphics output can be handled by the motherboard's IGP.
Idle/2D power mode: approx. 25W Blu-ray DVD playback mode: approx. 35W Full 3D performance mode: varies - worst case TDP 236W HybridPower mode: effectively 0W
For 3D graphics-intensive applications, the NVIDIA driver can seamlessly switch between the power modes based on utilization of the GPU. Each of the new GeForce GTX 200 GPUs integrated utilization monitors ("digital watchdogs") that constantly check the amount of traffic occuring inside of the GPU. Based on the level of utilization reported by these monitors, the GPU driver can dynamically set the appropriate performance mode (i.e., a defined clock and voltage level) that minimizes the power draw of the graphics card - all fully transparent to the end user.
The GPU also has clock-gating circuity, which effectively "shuts down" blocks of the GPU which are not being used at a particular time (where time is measured in milliseconds), further reducing power during periods of non-peak GPU utilization.
All this enables GeForce GTX 200 graphics cards to deliver idle power that is nearly 1/10th of the maximum power (approx 25W on GeForce GTX 280 GPUs).