Retina Monitors

I might've missed something here but my mid-2015 MacBook Pro 15in with AMD Radeon R9 M370X can drive a 5K display, like the Dell. You just need to use two DisplayPort cables (I think Apple refers to this as multi-stream technology). I'm not sure it can drive the LG display, though.

@Keir That makes sense. Thanks for the correction. Does that work with any additional Thunderbolt devices, or does it max out the Mac’s Thunderbolt capacity?

I'm driving two of the Dell 5Ks from a Mac Pro (late 2013) and one Dell 5K from an iMac 5K. In both cases, two mini-DisplayPort cables per monitor are required. However, Dell has discontinued production of this monitor. ;^(

Hi Michael, I think the key for the Dell 5K and its multi-stream transport is 2x DisplayPort 1.3 ports, rather than 2x Thunderbolt. I think this is how the 5K iMac pulls off the trick internally – again, it's just two DisplayPort channels going into the panel. It has the feel of a hack but it clearly works.

FWIW I came upon a MacRumors forum post saying that trying to run the Dell 5K monitor via the 2016 models (Thunderbolt 3 -> 2x DisplayPort hub -> Dell monitor) was a bit unreliable. I've no idea if that's still the case. Another CNET report from a while ago said that multistream transport can be unreliable in any case, but that was more Windows-focussed. In other words, I think this is still early days for Retina-quality external monitors. Apple's being very aggressive introducing ports and standards at the moment, but then I suppose they always have been that way. It'd be nice to see some standardisation start to take place, however, as with the old SCSI interfaces. I'll bet people with Thunderbolt 1 Macs feel very left behind, and my Thunderbolt 2 feels old-hat nowadays despite being a insanely speedy protocol. At least I can get Thunderbolt 2 -> Thunderbolt 3 connectors from Apple to use TB3 hardware (just get the Thunderbolt 3 -> Thunderbolt 2 adapter, designed for the MBP 2016 models, but which is reversible).