Display Power

This page discusses the power savings provided by the OLPC XO Laptop display architecture.

OLPC has consistently strived to provide a laptop with the lowest power consumption possible. The work on early XO-3 prototypes (which did not incorporate the OLPC display architecture) provides an excellent opportunity to measure the differences in power consumption.

System Idle and Display On

The first comparison is the power saved when the system is running with the display turned on. The XO-1.75 display subsystem consumes 424 mW (not including backlight or memory) compared to 565 mW on the XO-3 A1 prototype.

The real power savings comes from the transflective aspect of the OLPC display, which allows operation without a backlight in bright light, and operation with less backlight power indoors. The backlight in the OLPC display uses between 0 (in bright light) and 0.9W. The backlight in the display in the XO-3 A1 prototype uses between 0.5 and 1.9W ! Starting with the XO-1.75, the XO laptop even automatically turns off the backlight if the ambient light levels make it superfluous (such as outdoors).

Memory Power

The amount of power required by the host frame buffer memory is not included in the above numbers. This was done as the main system memory on the XO-3 only uses two DDR3 chips (128Mx16), versus the four used in the XO-1.75 (128Mx8).