# What is the maximum resolution that a Thunderbolt monitor can display?

The new MacBook Pro has a resolution of 2880 by 1800 pixels. I don't know how the GPU is connected to the monitor, but a more important question for me is: if there were standalone Retina displays, what was the maximum resolution it could considering only the bandwidth of external connections, such as 20 Gbps Thunderbolt, which is the fastest that I know of.

A simple calculation yields

• 20 Gbits / second

divided by

• 32 bits / pixel
• 60 Hertz

equals 10 Mpixel which supports:

• 16:10 3840 x 2400 WQUXGA
• 4:3 3648 x 2736
• That is a well calculated and insanely large viewport, more precisely it's equivalent to four 1920×1200 monitors stacked 2x2. Don't seem like this res is used by many – invert Jul 18 '12 at 11:57
• To add, "Most display cards with a DVI connector are capable of supporting the 3840×2400 resolution. However, the maximum refresh rate will be limited by the number of DVI links which are connected to the monitor..." ref – invert Jul 18 '12 at 12:00
• And let's not forget some new models come with two TB ports, which mean you can have 8 1920x1200 monitor!!! That's scary! – Philippe Gilbert Jul 23 '12 at 20:10
• HDMI 1.4 supports 1920×1200p60 at 48 bit/px and 4096×2160p24 at 30 bit/px because of it's 10 Gbps throughput (including overhead) – Jader Dias Jul 30 '12 at 13:47
• There's no need for a video signal to include an alpha channel, so wouldn't it be 24 bits per pixel? That would make it 13.8 Mpixel. – Mark Ransom Aug 15 '12 at 16:46

That would depend on a number of things. One thing that must be established, though, is the fact that thunderbolt carries a displayport signal. Source.

Since the max resolution of displayport is only limited by the available bandwidth, one can only guess how high a resolution could be supported through thunderbolt.

But since most of the bandwidth for Thunderbolt is provided by PCIe 2.0 x4 (16 Gbps), it doesn't seem likely that the displayport part of it carries more than 4Gbps (same as single-link DVI).

Compression and refresh rate would be the limiting factors, though, and with sufficiently advanced compression, retina displays could easily become viable.

Another solution might be, to include a small graphics chip in the external display. That would make it possible to transfer data over the PCIe bus, making the theoretical resolution 4 times that of single-link DVI.