If you, like me, were looking forward to seeing the arrival of a new Apple monitor with Retina display as well, you may not have been so pleased with the announcements of the special event held last Thursday. But know that there is a technical explanation for this delay.
Until last Thursday, all iMacs marketed by Apple were compatible with the Target Screen Mode feature (in English, Target Display Mode). This means that you can use your iMac as a monitor for another Mac using Mini DisplayPort or Thunderbolt cables. The new iMac with Retina 5K screen, however, does not support this feature. But why? Most likely for the same reason that Apple did not launch a new 5K display: bandwidth limitation.
Transforming the iMac with Retina 5K screen into an external monitor for a Mac mini, Mac Pro or MacBook Pro, for example, would only be possible via a Thunderbolt / Thunderbolt cable. The problem is that Thunderbolt 2 technology uses the DisplayPort 1.2 specification, which is not able to handle such a large resolution. The result is that, even with support for 4K monitors, machines like Macs Pro and MacBooks Pro with Retina display are not able to handle this 5K display of the iMac.
We recently commented on the DisplayPort 1.3 specification (this one, with support for resolutions up to 5K via a single cable). That is, most likely we will have to wait for the implementation of this technology so that everything works perfectly according to Marco Arment, it should only arrive when Intel launches the Skylake family, successor to Broadwell (which has not even been launched yet).
That is, it is possible that an Apple monitor with a resolution of 5K will only hit the market there for 2016. And the worst part of it is that no current Mac will be compatible with it (including the Mac Pro).