What is the max resolution output by the HDMI port of the MacBook Pro Retina?

Solution 1:

If it's HDMI 1.4 as noted above, it should support "4k" resolution (4096×2160p24)

http://en.wikipedia.org/wiki/HDMI#Version_1.4

Solution 2:

The hardware on the mid-2012 Retina MacBook Pro technically supports up to 4K resolution over HDMI.

However, OS X seems to limit the resolution to 1080p60 (1920x1080 at 60 hertz).

The NVIDIA drivers on Windows support higher resolutions, for example I have no problem using an Asus 27" 2560x1440 at 60 hertz over HDMI on the rMBP (Windows 8.1 in Bootcamp). The same display will only go up to 1080p when run on OS X Mavericks (10.9).

It might be possible to enable higher resoutions on OS X via HDMI using SwitchResX (I haven't tried).

Solution 3:

Given that the new (late-2013) Mac Pro supports 4k over HDMI, this is wrong.

I believe HDMI is limited to full HD resolution, i.e., 1080p (1920x1080), so nothing can drive a larger screen through that.

Even if HDMI isn't restricted to 1080p, 2560x1600 requires dual-link DVI and I'm quite certain that HDMI doesn't have those pins, restricting it to the resolutions single-link DVI is capable of (2,098 × 1,311).

Your best bet is to use the 10/100 Fast Ethernet adapter over USB.