Dell C5517H User Manual page 72

• Show only on...: Display the status of a particular monitor. This
option is typically chosen when the laptop is used as a PC so the
user can enjoy a large external monitor. Most current laptops support
mainstream resolutions. As shown in the figure below, the resolution
of the laptop monitor is only 1280 x 800, but after connecting a 27"
external LCD monitor, users can immediately improve their visual
enjoyment to 1920 x 1080 Full HD quality.
72 Setting Up Your Monitor
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