video card - use a shared terminal, shared thin client, or desktop sharing software if display required. Use motherboard video output - typically low 3D performance and low power. Select a GPU based on low idle power, average wattage, or performance per watt. Display Unlike other display technologies, electronic paper does not use any power while displaying an image. CRT monitors typically use more power than LCD monitors. They also contain significant amounts of lead. LCD monitors typically use a cold-cathode fluorescent bulb to provide light for the display. Some newer displays use an array of light-emitting diodes (LEDs) in place of the fluorescent bulb, which reduces the amount of electricity used by the display. Fluorescent back-lights also contain mercury, whereas LED back-lights do not. A light-on-dark color scheme, also called dark mode, is a color scheme that requires less energy to display on new display technologies, such as OLED. This positively impacts battery life and energy consumption. While an OLED will consume around 40% of the power of an LCD displaying an image that is primarily black, it can use more than three times as much power to display an image with a white background, such as a document or web site. This can lead to reduced battery life and energy usage, unless a light-on-dark color scheme is used. A 2018 article in Popular Science suggests that "Dark mode is easier on the eyes and battery" and displaying white on full brightness uses roughly six times as much power as pure black on a Google Pixel, which has an OLED display. Apple's iOS 13 and iPadOS 13 both feature a light-on dark mode, which would be possible for third-party developers to implement their own dark themes. Google's Android 10 features a system-level dark mode. Materials recycling Recycling computing equipment can keep harmful materials such as lead, mercury, and hexavalent chromium out of landfills, and can also replace equipment that otherwise would need to be manufactured, saving further energy and emissions. Computer systems that have outlived their particular function can be re-purposed, or donated to various charities and non-profit organizations. However, many charities have recently imposed minimum system requirements for donated equipment. Additionally, parts from outdated systems may be salvaged and recycled through certain retail outlets and municipal or private recycling centers. Computing supplies, such as printer cartridges, paper, and batteries may be recycled as well. A drawback to many