Old MacBook Pro, New Monitor (Mini Displayport -> USB-C)?

August 2, 2020 9:34 AM

Is there an adapter that will allow a 201x-era MacBook Pro to display on a 2020 4K monitor with only USB-C inputs?

I have a 2012 MacBook Pro that's still an acceptable workhorse for the things I need it for. I run several different second monitors via an assortment of Mini Displayport dongles I've collected over the years (VGA, DVI-2, HDMI).

I have been given a nice 24" LG 4K monitor (24MD4KL-B) and would like to drive it from my old MBP.

The MBP only has a Mini Displayport / Thunderbolt-2 output, and the LG monitor only has USB-C inputs. There are a bunch of USB-C - to - Mini Displayport adapters, but they all say "unidirectional," and as far as I can tell, it's the wrong direction.

Is there an adapter that goes in the right direction? Is it even possible to do that? Or can I go from one of my dongles (DVI-2, HDMI) to USB-C?

posted by spacewrench to Computers & Internet (6 answers total)

Looks like this plus a thunderbolt cable may do it: Apple tb2 to tb3 adapter. The item copy definitely anticipates this use case, but ymmv
posted by wotsac at 9:43 AM on August 2, 2020

I upgraded my 2012 retina MacBook Pro a few years ago because at the time my research found that it was incapable of driving a 4K monitor. Maybe that has changed since then, but I doubt it.
posted by aubilenon at 10:56 AM on August 2, 2020

Apple's adapter that wotsac linked to does work bidirectionally to connect Thunderbolt 2 computers to Thunderbolt 3 monitors, but I've found it to be finicky. Definitely make sure you use a true Thunderbolt cable (with a "thunderbolt" icon on it) and not a random old mini displayport cable (with a rectangular "monitor" icon); they have the same connector shape but not the same capabilities.

Another question will be whether your MacBook Pro can actually support a 4K device at full resolution. If you have a 15" with a Retina display then I think you should be OK even if it's technically unsupported. MacTracker says the 2012 models were limited to outputting 2560x1600 but I believe that's outdated info from the original shipping specs and they are actually capable of slightly higher resolutions.

If you can put the monitor into "Multistream" (or "MST") mode using its on-screen settings you might get full resolution, but I think at most you'll only get a 30 Hz refresh rate and the laptop will get hot (which could mean extra fan noise). If not you'll be limited to a scaled resolution which may or may not be acceptable for your purposes. Just something to consider before you shell out for additional dongles and cables.
posted by bcwinters at 11:02 AM on August 2, 2020

Thanks all! My MBP is a 13" non-Retina, so it's certainly unlikely to have the graphics hardware to run a 4K device. It does OK on random 1920x1080 and 1680x1050-ish monitors, but this would be the first time I'd tried to go bigger than that. It's not worth buying a $50 dongle for this one obsolescent use case. I'll just adjust my workflow to use a more-recent computer with this nice monitor.
posted by spacewrench at 11:15 AM on August 2, 2020

Mactracker (from bcwinters' answer) is a handy tool! You can type in your Mac's serial number and get all the specs on it. My MBP has a max external resolution of 2560x1600, so it's fine for my smaller monitors, but probably wouldn't be happy with the LG's 3840x2160.
posted by spacewrench at 11:24 AM on August 2, 2020

I can confirm this will not work. No need to wonder if it might have.
posted by 10ch at 9:55 AM on August 3, 2020