Power Modes
Optimal Power – This option was introduced with the GeForce GTX 1080 in driver version 368.22 back in May of 2016. Until then only two modes existed, Adaptive and Prefer Maximum Performance. After then, now Optimal Power is the default setting. Similar to the other options voltage, GPU clock speed and memory clock speed are controlled, as well as something else.
Basically, when your PC is idle and the screen is not changing the GPU will not render new frames, instead it re-uses frames rendered in the framebuffer. In theory, this should reduce power without affecting performance. This is all about improving Idle power.
Adaptive Power – Adaptive Power is another option you can select, it use to be there before Optimal Power even existed and used to be the default setting a long time ago. According to the NVIDIA Control Panel Adaptive allows the graphics driver to automatically determine the proper performance state based on GPU usage.
It’s a big vague in specifics, but technically it can control voltage, GPU frequency, and memory frequency as well. It should strike a balance between using Optimal Power in Idle states, and maximum performance in heavy 3D loads automatically.
Prefer Maximum Performance – This one does as it says, it maintains the card at its maximum performance state no matter what, even in Idle. This means higher Idle Wattage, and heat just sitting there doing nothing. The big question is will it help us with gaming performance?
This one is a bit of a legacy setting, it existed at a time when things like 2-way or 3-way or even 4-way SLI didn’t always accelerate each GPU at maximum potential. In drivers of years past it was recommended that you set “Prefer Maximum Performance” if your SLI configuration was experiencing little to no performance gains. Forcing the highest maximum performance power mode would fix the issue and force all GPUs in an SLI configuration to run at their full-speed in games for the best SLI scaling. So, it did have a big effect, at one point. The question is, does it still?