Officially, Apple lists the Macbook Pro as supporting two 2560*1600 displays via HDMI and Thunderbolt. But they may only say this because there aren't any higher resolution displays in the consumer market. DisplayPort 1.2 is over 2 years old, and I believe the standard does support 3840*2160 resolution, which is quite likely what we will see (if not 3840*2400 resolution - if that would work too) when Retina desktop displays are released. And in a few years they're probably going to be available from a number of manufacturers, - Apple, Dell, etc. But I don't even know what version the new Retina Macbook Pro's DisplayPort is. But what current Macs could actually support these resolutions? The Macbook Pro can drive 3840*2400 internally (which is downscaled to fit the screen). Is it technically capable (perhaps a software update is needed) of putting out Retina resolutions through Thunderbolt and/or HDMI, so that we're not forced to buy a new computer should we want to drive one or more Retina desktop displays in the future? May well be too soon to know this. But I've dug around and not found anything conclusive. Does anyone know anything?