We have a headless mac mini server running Mountain Lion 10.8.4 for testing and maintain several additional headless mac minis for clients. Since OS 10.7, we’ve had a constant issue using ARD (Apple Remote Desktop) with these macs. The display graphics on the remote machine are terrible with gibberish graphic blocks until you switch to the Finder on the mini, open a new window and drag it around like painting with a square…then poof, all of the graphic junk would clear up and the display would look correct. Reconnect in a few hours or days and the problem would return.
Finally, an answer has been found and thanks to Tristan Bettany for documenting it. The solution is cheap and easy, just combine an Apple VGA adapter and 100 ohm resister to prevent the low power mode in the graphics card that causes this artifacting. Head over to Tristan’s blog for details on the why and how to fix this graphical issue with headless Mac Minis & Apple Remote Desktop