Hacker News Reader

Most likely, your 2013 Mac Pro won't be able to do that because a single cable / single bus DisplayPort v1.2 cannot provide the bandwidth for 5k (DP v1.2 provides about 17.3Gbps which is insufficient).

Unless Apple provide a multi-cable solution for the 2013 Mac Pro when the 5k Thunderbolt display comes out, you won't be able to take advantage of 5k displays on it.

My prediction is that we'll see an updated Mac Pro that also uses the Haswell Xeons (2013 Mac Pro uses last gen Ivy Bridge) and also DP v1.3 (which can support 5k displays).

Anandtech has the following message in their story:

Update: And for anyone wondering whether you can drive the 5K display as an external display using Target Display Mode, Apple has confirme that you cannot. http://www.anandtech.com/show/8623/hands-on-apples-imac-with...

These aren't monitors, they're full computers. You can't even use them as external monitors like the old iMacs could.

Why would you do that?

Well, because I need high-ppi displays:) That's the main reason I changed my 2011 iMac to the 2013 Mac Pro. Now it's weird: either a single 5k-screen with the new iMac, or two worse 4k-screens on Mac Pro.