How To: LG UltraWide 2560x1080 60Hz on a Mac

July of 2015, with great excitement I got a hold of an LG UltraWide 29" (21:9) monitor (29UM57).  This monitor ONLY has two HDMI ports... no other ports. Should be good right? You'd think.

On my Windows PC, it was truly plug and play and worked flawlessly with zero effort. But on my late 2013 iMac running Yosemite, not so much. The best I could get it to do was I beleive 1080p. Evidentely, at the least, they (Apple) think that anything plugged into HDMI "HAS" to be a television and televisions only do 1080p at the greatest. Thanks for protecting us from ourselves Apple, or trying to force us to just buy your stuff at 3 times the price, or whatever your deal is.

There were some scripts out there written by people way smarter than me that were supposed to tell the Mac not to treat the monitor as a TV. I tried the script from a few sites and they all had errors when you'd try to run one. I finally got one that worked. Problem is, although the Mac no longer said the monitor was a TV in the about this Mac screens, the results were no better. Still just 1080p no matter what.

After night one of around 8 hours of trolling Google, the best I could get was with SwitchResX and it wasn't perfect. I was able to get a crisp screen at 2560x1080 at 52mhz, not 60mhz.

Well on night two, super late, maybe 12 hours into the whole deal, I stumbled onto something someone was gracious enough to write. I figured no way was this going to work as I'd already tried numerous things that we supposed to work to no avail. BUT IT WORKED!

Before I get into the solution, let me say, the reason I am writing this article is, I wanted to give back and help anyone else if possible so they didn't have to go through this mess. The problem is, every thread out there wanted me to create an account before posting. I don't need another zillionth account that I will never use. I'm sick of that. So, no account, just an article.

Lastly, this is not a message board so you can't post any feedback. I am not an expert and can offer no additional advise. I am a very busy business man and sorry to say, I do not have time to answer any questions, besides, I am sure I don't know anyway. SO, if it helps you, awesome! That was the intent. If it doesn't, or you have something else to say because you have way too much time on your hands, well, I do not. So please don't bother :)

What I Did:

  • Install SwitchResX (available on the Mac store for free)
  • Download Mac-Pixel-Clock-Patch and save it to your Downloads folder. It is available here https://github.com/Floris497/mac-pixel-clock-patch, and this guy deserves all of the thanks!!!
  • Note: You will need to disable system integrity protection (rootless) otherwise you will get errors when running the script and it will not work. Reboot your Mac and when you hear the bootup chime, press and hold the COMMAND key and R. You will get the Mac recovery screen. Use the Utilities menu at the top of the screen and select Terminal. In terminal type "CSRUTIL DISABLE; REBOOT". Reference: http://osxdaily.com/2015/10/05/disable-rootless-system-integrity-protection-mac-os-x/
  • Open Terminal on your Mac and run the following commands:
    • cd ~/Downloads
    • chmod +x macPixelClockPatcher.command
    • ./macPixelClockPatcher.command

Now 2560x1080 60mhz will show up in SwitchResX. Note: After installing SwitchResX, you access it via Settings. It is an additional settings option in the main settings screen on your Mac. Also, if you place a check next to it in SwitchResX (I believe it is a checkbox for "Home", it will show up in your Display properties in your Mac settings.

For reference, these are the SwitchResX properties in case anyone ever has to manually enter them:
2560 1080
64 3
64 10
96 18
224 31
2784 1111
66.659 60.000

For reference, these are the SwitchResX where I was able to get 52mhz (not optimal but clean enough):
2560 1080
47 7
32 20
80 12
160 39
2720 119
58.188 52.000

That's it. I hope it helps someone save 12+ hours!  Not real happy with Apple as I am typing this on my Samsung PC that actually works as expected.