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Setup: New System76 Lemur laptop running Ubuntu Unity 12.10 is connected via VGA cable to a new dell Ultrasharp u2312hm 23-inch monitor.

Symptom: The Dell monitor has an annoying flicker, like high-speed waves of darkness passing over it, pretty subtle at times, but very annoying at others. The flicker seems to increase when I type or move the mouse.

Why I don't think it is the Dell monitor's fault: I connected the monitor to an old Dell laptop and there was no flicker.

Question: Is there a known solution?

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Copied from System76 Support: "While the laptop doesn't have a DVI port, you can use a DVI-HDMI cable or adapter to plug it into the HDMI port. This will result in a significantly clearer picture. The problem with VGA is that because it's an analog connection, at that resolution the signal is very susceptible to EM interference from other components in the system. Eve a small amount of EM leakage (within normal levels for this laptop) can cause visible corruption. Using a lower resolution or a digital connection will solve the problem." – zkurtz Dec 21 '12 at 18:33
up vote 4 down vote accepted

Solution to my own question: Stop trying to use a VGA connector. Instead, use something digital like HDMI or DVI. My computer had HDMI and my monitor had DVI; an adapter between those two ports gave me a perfect image on the monitor.

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