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Help needed on macbook pro 2017 + 4K LG 27UD68-W

F

furfing

macrumors member
Original poster
Jan 20, 2012
48
8
Hello All,
I have a macbook pro 2017 full option.

I just bought the 4k screen LG 27UD68-W 4K Monitor.

Everything is lagging, the mouse the windows etc.... it's terrible also it makes my eyes so tired.

I noticed i am running at 30hz which might be the reason.

How could i fix this ? I would like ideally to directly connect the monitor whichs only has hdmi port to USB-C without the adapter ? Would this helps ?

So far i use the cable provided by LG and a HDMI 1.4B to USBC adaptor.

Thanks for your kind help
 
Make sure your HDMI cable AND the adapter is capable of supporting 4k at 60Hz. It is likely the adaptor does not. Believe you will need a HDMI 2.0 cable at least.

It works much better if you use Display Port for the connection. I have a similar model from LG and even with the right cables, there was some lag and stuttering. Once my TB3 dock came in I switched to Display Port and it made worlds of difference.
 
OP wrote:
"So far i use the cable provided by LG and a HDMI 1.4B to USBC adaptor."

That's your problem. (HDMI 1.4)
You need HDMI 2.0 (with a high-speed HDMI cable) to get 60hz.

Actually, I believe USB-c to displayport would be the best option.
 
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thx u !

i already orderered hdmi 60hz... shall i cancel to get displayport ?
 
I have 43' LG 4k monitor and it has few HDMI and one Display port. I had best success with USB-C to DisplayPort cable for my 2017 MBP to my monitor. Gives least headaches, but even there I tested three different cables before I found one which does not reboot the monitor randomly. I tried also through Thunderbolt USB-C hub/with Display Port to Display Port - that works also. When I tried to use any HDMI I always got only 30Hz refresh - it seems to be difficult to guarantee all components are proper version.
 
Fishrrman said:
OP wrote:
"So far i use the cable provided by LG and a HDMI 1.4B to USBC adaptor."

That's your problem. (HDMI 1.4)
You need HDMI 2.0 (with a high-speed HDMI cable) to get 60hz.

Actually, I believe USB-c to displayport would be the best option.
Click to expand...

Sorry wrong model number, i have the 88 with usb c port.
 
Last edited:
furfing said:
How could i fix this ? I would like ideally to directly connect the monitor whichs only has hdmi port to USB-C without the adapter ? Would this helps ?
Click to expand...
I have the exact same monitor (LG 27UD68-W) and it does have two HDMI and a Display Port input.

If you want 4K@60 Hz I would highly recommend getting either a USB-C/TB3 to DisplayPort adapter, a Thunderbolt 3 docking station, or a USB-C to DisplayPort cable. Either one of these should work. I've been using this display with a 2016 13" MacBook Pro and a CalDigit TS3 Lite TB3 dock for eight months now, and it's connected to the docking station via DisplayPort cable.
 
Double check the monitor specs as well. I have both Dell and Acer 4K displays. Both of them provided DisplayPort and HDMI cables in the box. Yet neither of them actually support 4K @ 60Hz over HDMI, that’s limited to DisplayPort only
 
According to LG, the 27UD68 supports HDMI 2.0: http://www.lg.com/us/monitors/lg-27UD68-W-4k-uhd-led-monitor

I've never tried using the included HDMI cable with an HDMI 2.0 device due to lack thereof it so I can't say whether or not it works and if so whether it works on both HDMI ports on only one of them. What I can say for sure is that it works with the included DisplayPort cable with the 13" 2016 MBP using the CalDigit TS3 Lite Thunderbolt 3 docking station as well as on the 15" 2015 MBP using an mDP to DP cable:

lg27ud68.png
 
Hello,

I just received the HDMI cable which is rated as 3840*2160/60hz (HDMI 2.0) however on the LG 27UD68-W in my mac book pro 2017 i still can see only 30hz with very fewer resolution than my hdmi 1.4b cable...

What could be the issue ?
Do i need to go for Display port ?

Thx
 
Can i use a display port adapter to usbc i will connect to it the provided lg display port display.

in china i cant find the display port to usbc adapter... thx
 
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furfing said:
Hello,

I just received the HDMI cable which is rated as 3840*2160/60hz (HDMI 2.0) however on the LG 27UD68-W in my mac book pro 2017 i still can see only 30hz with very fewer resolution than my hdmi 1.4b cable...

What could be the issue ?
Do i need to go for Display port ?

Thx
Click to expand...
It is always better to go with Displayport. But now that you already got the hdmi adapter, try this: Go to the Settings on your montior and look for a setting similar to something like „Ultra HD Deep Color“. That Setting has to be turned on to enable hdmi 2.0 and therefore 4k at 60hz.
 
elmacci said:
It is always better to go with Displayport. But now that you already got the hdmi adapter, try this: Go to the Settings on your montior and look for a setting similar to something like „Ultra HD Deep Color“. That Setting has to be turned on to enable hdmi 2.0 and therefore 4k at 60hz.
Click to expand...
Thx it works !!!
 
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furfing said:
Hello,

I just received the HDMI cable which is rated as 3840*2160/60hz (HDMI 2.0) however on the LG 27UD68-W in my mac book pro 2017 i still can see only 30hz with very fewer resolution than my hdmi 1.4b cable...

What could be the issue ?
Do i need to go for Display port ?

Thx
Click to expand...
I had the same issue initially with my Mac mini 2018 on my 27UD68, it turned out that when I turn on "HDMI deep color support" and plug the HDMI cable into HDMI2, restart and it running at 4K*60hz now.

But I still feel the color is kind of wired, might be spoiled by iMac 5K.
 
elmacci said:
It is always better to go with Displayport. But now that you already got the hdmi adapter, try this: Go to the Settings on your montior and look for a setting similar to something like „Ultra HD Deep Color“. That Setting has to be turned on to enable hdmi 2.0 and therefore 4k at 60hz.
Click to expand...

Thanks for this post! I have two LG 27UD58P-B monitors connected to a new 2018 mac mini. I was getting 30Hz via HDMI 2.0 on both monitors until I enabled Ultra HD Deep Color as you suggested & rebooted. The reboot was necessary for some reason.

I used HDMI 2.0 cable that came with monitor for one of them, then purchased this USB-C to HDMI 2.0 cable for the other: http://a.co/d/8DCMORh
 
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BananaX said:
4K LG 27UD68-W
Any good?
Click to expand...

That particular model is actually a generation old at this point, but I would highly recommend LG 4K monitors for use with Macs. They have quite a few models outside of the Ultrafine series that Apple sells. The LG 27UD68 the OP mentioned is a good monitor but it does lack a height adjustable stand, which is a must-have for me. The LG-27UD68 is actually still sold at a lot of online retailers. They actually made a slightly tweaked version, 27UD69-W which I own which is almost identical except it includes a height-adjustable stand. I run it using an Elgato Thunderbolt 3 dock via the DisplayPort and it's excellent. A coworker of mine runs 2 of them with his 13'' MBP. However this model was sold almost exclusively thru BestBuy and has been discountinued, though you can still find some.

The current generation, which I'd personally recommend, are models LG 27UK600 and LG 27UK650. Simply put similar displays and the 600 model has no adjustable stand and the 650 model does include a height-adjustable stand. I also own a 650 model and would recommend it. These models support HDR while the previous generation do not, though it is worth noting macOS can't run HDR content.

If you're looking to get a deal, you can probably get a last-gen LG-27UD68 for a pretty sweet deal around Cyber Monday/Black Friday. I'd imagine with those being older, someone will bound to have a good deal on one.
 
Question to tack on here: I just purchased an LG 27uk600w for my 2017 MBP and was able to connect it with an HDMI+USB-C adapter but after trying to throw a Displayport+HDMI adapter into the mix the monitor stopped appearing as an option on my MBP, even after switching back to the HDMI only setup. How do I get it to appear again? Did I break something with the monitor? Thanks in advance for any wisdom!
 
apzucker said:
Question to tack on here: I just purchased an LG 27uk600w for my 2017 MBP and was able to connect it with an HDMI+USB-C adapter but after trying to throw a Displayport+HDMI adapter into the mix the monitor stopped appearing as an option on my MBP, even after switching back to the HDMI only setup. How do I get it to appear again? Did I break something with the monitor? Thanks in advance for any wisdom!
Click to expand...
Do you have the correct input selected on your LG Monitor?

Either way you'll want to connect to the monitor using a USB-C > DisplayPort cable as the HDMI cable using an adapter will not run at a full 60Hz (it'll run at 30Hz). By using DisplayPort you should get 4K @ 60Hz. They sell cables on Amazon that eliminate the need to use an adapter. I have a very similar monitor (LG 27UK650) with this setup.

Not sure why else you wouldn't be able to see the monitor with your Macbook. May be good to power cycle both your MBP and the display, as well.
 
Thanks for the response! I was able to get it working again by restarting in safe mode and it's been working since then. Waiting for a new USB-C > DisplayPort cable to arrive to i can get full resolution at 60hz :)
 
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