Your iPad 3 can now act as a stunningly high quality HIDPI display for a Mac or PC with the help of a great iOS app called Air Display. A completely wireless solution, Air Display takes advantage of OS X Lion and Mountain Lion HIDPI display mode to turn the new iPad’s 2048×1536 display into an ultra-crisp 1024×768 retina display. Setting up Air Display to turn that new iPad into an external retina