Problem:

How do I save power and reduce heat with my nVidia GPU?



Solution:


This guide only covers dedicated nVidia GPUs. Unfortunately, there isn't much to cover. Recent driver versions have all but removed user control over the GPU power profile. The GPU adjusts the profile automatically according to load, and lower clocks are used on battery.

nVidia cards in Windows XP: Make sure you use a driver that supports PowerMizer. Newer driver versions allow very little control: you can only select whether or not you want the GPU speed to be capped to a lower value when the notebook runs on batteries. This can be done only in the Advanced mode of the nVidia control panel. If you have such a driver, make sure the GPU is capped when on battery.

With older driver versions, you have more freedom. You can select among three power profiles: Power Saving (aka Standard 2D), Balanced (aka Low-Power 3D), and High Performance (aka Performance 3D). Go to the GPU driver config page (right click on the desktop, Properties, Advanced, Settings, GPU): select Power Saving for battery, and Max Performance for AC Power (if you're gaming or using GPU-intensive apps); or Balanced for AC Power (if you don't game nor use GPU-intensive apps).

nVidia cards in Vista: In theory, the GPU power profile should be controlled via the Vista power profile (see below for the procedure). In practice, I have found that the driver ignores the Vista profile settings, and the GPU profile adjusts automatically according to load. Also, lower clocks are used on battery. Nevertheless, this lack of control could have been due to a problem with my particular setup, so I cover the (theoretical) procedure for GPU profile control below.

I assume your laptop uses the PCI Express interface for the GPU. That is the case for virtually all current dedicated GPUs. If your GPU is integrated, those are much more power-efficient, and the default power profiles will probably be good enough for you. Click the battery icon in the system tray, then select More Power Options, and from the ensuing page, click Change plan settings, and from the next page select Change Advanced Power Settings. Power saving profile: Select from the dropdown list the powerplan(s) that you use for conserving power (by default, Vista uses Battery Saving on battery and Balanced on AC power). Look for the PCI Express setting, expand it, and set the Link State Power Management to Maximum Power Savings both on battery and on AC power. High performance profile: Select from the dropdown list the powerplan(s) that you use for high performance (e.g., High Performance). Expand PCI Express setting, and set the Link State Power Management to Off both on battery and on AC power. Now you only need to use a power-saving Vista profile when you want your GPU to consume less power, and a high-performance Vista profile when you want it to go full-speed.

It is possible (in theory and practice) to also lower the clocks for the GPU profiles, using software such as Riva Tuner. This can be used to emulate to an extent explicitly controlled GPU profiles.