Apple’s current 27-inch Thunderbolt monitor is over five years old and badly in need of an update. However stunning a 2560×1440 27-inch display might have been in 2011, it’s not worth its $999 price tag today. New rumors suggest Apple is working on an updated 5K version of the monitor with Thunderbolt 3 support, and Apple may have included its own onboard GPU to ensure the display is always driven by a compatible graphics card. The panel itself is reportedly very similar to the Retina panels Apple already uses with support for the DCI P3 color standard.
According to 9to5 Mac’s sources, stock of the current Thunderbolt display is drying up. That’s typically a sign that Apple intends to launch an imminent product update, and that’s where things start to get interesting. One of the problems with shipping an independent 5K display is that it’s difficult to ensure that the majority of customers who might buy such a display can actually use it with their current hardware. This is particularly true of laptop GPUs, which tend to be less powerful than their desktop counterparts. One of the problems with calling this higher resolution “5K” is that it implies only a modest improvement over 4K. 4K was a great marketing term, because the new resolution happened to contain 4x the pixels of 1080p. 5K sounds like it’s just a 25% improvement over 4K, but it actually contains 1.77x more pixels — and 14.75 megapixels is enough to bring some laptop GPUs to their knees, even on the desktop.
Apple’s solution to this problem is apparently to equip an external GPU directly in the monitor. While that might seem unusual, it actually makes a great deal of sense. Apple already built itself a custom timing controller chip for its 2014 5K iMac, and it can keep on using that chip with an integrated GPU.
There’s one thing that makes this move a tad unusual. The signal is carried via Thunderbolt 3, which means only future Macs with Thunderbolt 3 connectors would be able to use the hardware at 5K (the display would remain compatible with older Macs when used at a lower resolution). Then again, Apple is known for positioning itself on the cutting edge of technology standards, even when those standards aren’t accessible to most people.
There’s no question that Apple can drive 5K within the display, since they’ve been doing it for years with the 5K Retina iMac. The bigger question is whether external Thunderbolt 3 has enough horsepower to handle the signal. While Thunderbolt 3’s 40Gbps transfer rate is more than enough bandwidth for 5K, TB3 uses DisplayPort 1.2, not the newer DP 1.3 or 1.4 standards that explicitly allow for 5K.
I suspect the reason Intel can support 5K over DisplayPort 1.2 is because Thunderbolt 3 implements up to 8 lanes of DisplayPort 1.2 (there are four lanes in a typical DP1.2 configuration). This is admittedly speculation on my part, but it makes sense — if Intel can gang those lanes together it would have more than enough bandwidth to feed a [email protected] stream.
We’ll have to wait and see what Apple announces before we know how the company has pulled this off, but it’s interesting to see more companies adopting external graphics, even if this is the first time someone has shoved a GPU into a monitor. Intel collaborated with both AMD and Razer in developing their XConnect external GPU hardware, and while there may not be a direct link between Intel’s work on Thunderbolt 3’s graphics certification and Apple’s rumored 27-inch iMac, we’d be surprised if some of that work didn’t carry over into products like this. Supposedly OS X will be capable of hot-swapping between the display’s GPU and the integrated hardware on a laptop or Mac Pro, though there won’t be any way to use the two graphics cards together.