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4K at 60Hz on 12" rMB Hack: Monitors, Cables & Adapters That Work

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The first post of this thread is a WikiPost and can be edited by anyone with the appropiate permissions. Your edits will be public.
Hellhammer

Hellhammer

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Original poster
Dec 10, 2008
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USB-C has four high-bandwidth lanes that can be dedicated to either USB 3.1 Gen 1 (i.e. USB 3.0 - 5Gbps) or DisplayPort 1.2. In addition to these four lanes, USB-C has separate USB 2.0 and power lanes that are available at all times. Running 4K at 60Hz requires the bandwidth of all four lanes, which would limit USB to 2.0, and for some reason Apple has disabled this, leaving users with no proper 4K support. The MacBook supports 4K at 30Hz just fine, but most users have found this to be unusable since even moving the cursor has a notable lag.

The Hack

While this topic surfaces quite frequently, very few seem to be aware of a hack that enables 4K at 60Hz. The hack is called mac-pixel-clock-patch-V2 and user reports here indicate it works flawlessly and is smoother than the SwitchResX 50Hz hack since the panel can run at its native 60Hz refresh rate. Basically, the hack forces all four high-speed lanes to be dedicated to DisplayPort 1.2, meaning no USB 3.0, but USB 2.0 and power is still delivered assuming that the device/cable/adapter supports these.

This Thread

The purpose of this thread is to act as a general wiki database for user experiences and displays, cables and adapters that work. This is a wiki post, meaning anyone can modify this with the idea of keeping this as up to date as possible, so people can quickly find information and buy supported equipment.

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Displays

Lenovo ThinkVision X1 - 27" 4K IPS $669

Reported to be working here. Has built-in USB-C port for video, data and charging, so no adapter needed. Built-in mic, camera and speakers work as well. However, the included USB-C cable does not work - see below for cables that have been confirmed to work.


Adapters

No specific adapters confirmed yet. This post mentions "a cheap USB-C to DisplayPort" working and technically all USB-C to DisplayPort adapters should work.


Cables

Apple USB-C Cable - NOT WORKING

Only for charging - cannot be used for video or data.

Monoprice USB 3.1 USB-C Cable 3ft - WORKING

Confirmed to be working here.

Belkin USB 3.1 USB-C Cable 3ft - NOT WORKING

Supports charging and perhaps data, but no video as reported here.

AUKEY USB 3.1 USB-C Cable 90cm - MIXED REPORTS

One user is reporting it works, whereas another one reports it not working.

Tenswall USB 3.1 USB-C Cable 3.3ft - NOT WORKING

Reported here.
 
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Asus PB287Q - 28" 4K TN $429

I (w0rd3r) just tested it and it works at 1920 x 1080 HiDPI @ 60Hz, but no other scaled resolution like 1800p or 1440p. I used a Victsing adapter (http://www.amazon.com/dp/B0191PRS72/), so I'm not able to test a Clamshell mode, where I assume I'll be able to use every scaled resolution @ 60Hz.
 
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w0rd3r said:
Asus PB287Q - 28" 4K TN $429

I (w0rd3r) just tested it and it works at 1920 x 1080 HiDPI @ 60Hz, but no other scaled resolution like 1800p or 1440p. I used a Victsing adapter (http://www.amazon.com/dp/B0191PRS72/), so I'm not able to test a Clamshell mode, where I assume I'll be able to use every scaled resolution @ 60Hz.
Click to expand...

Does HiDPI mean that it's running at 4K, but with everything scaled to 1080p? What was the resolution before you applied the patch? Just trying to make sure you're running it at max resolution.
 
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Hellhammer said:
Does HiDPI mean that it's running at 4K, but with everything scaled to 1080p? What was the resolution before you applied the patch? Just trying to make sure you're running it at max resolution.
Click to expand...

Indeed, that is what I meant. Looking through the Monitor menu, I can clearly see he receives 3840 x 2160 @60Hz. But the MacBook makes it look like 1080p HiDPI (so it is scaled down to 1080p, but looks really sharp thanks to the 4K display).

I forgot to add that I managed to run it 4K@60Hz only via mirroring.

Before applying the patch, I ran the display at 2160p @30Hz. I wish I could use different scaled resolutions though. Can you? If you need screenshots of a system report, here they are
 

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Is this hack only enabled when connected to a 4K monitor and everything back to normal settings when disconnected?
 
Cool. Seems crazy not a default option rather than system hack. I'm no computer expert, though.
 
It's probably not a system option because Apple doesn't want to explain why USB is running at 2.0 speeds when a 4k @ 60Hz display is connected.
 
Regarding the clamshell mode, I'll be able to test it in the upcoming weeks since I'll receive the KADI Port (with 2 USB-C).
https://www.kickstarter.com/projects/thekadiport/the-kadi-port-a-macbook-essential
So I'll use one with the charger and the other one with the DisplayPort adapter I mentioned earlier.

I still don't know if I'll be able to use every scaled resolution just like an iMac or a MacBook Pro. If anyone can tell me which resolutions are available (as I said, for me it only works @1080p HiDPI @60Hz. Others are not available or @30Hz) it would be great!
 
tomislavf said:
It's probably not a system option because Apple doesn't want to explain why USB is running at 2.0 speeds when a 4k @ 60Hz display is connected.
Click to expand...

Some Intel slides also mentioned that 4K may require additional cooling on Core M chips, so Apple might have disabled it to avoid excessive throttling and other heat issues.

w0rd3r said:
I did not
Click to expand...

Give it a try. You should be able to run your 4K display at non-HiDPI resolutions as well, including 3840x2160 at 60Hz.
 
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Hellhammer said:
Give it a try. You should be able to run your 4K display at non-HiDPI resolutions as well, including 3840x2160 at 60Hz.
Click to expand...
I'll see if I can, but I've not found anyone able to tell me if it had every option or not.
1080p HiDPI is (unfortunately) useless for me, I'd like 1800p or 1686p.

Do you know if it works only in mirroring mode for others as well as for me ?
 
w0rd3r said:
I'll see if I can, but I've not found anyone able to tell me if it had every option or not.
1080p HiDPI is (unfortunately) useless for me, I'd like 1800p or 1686p.

Do you know if it works only in mirroring mode for others as well as for me ?
Click to expand...

Well here's a screenshot where it's running without mirroring.

HCUB6QN.png


From https://v2ex.com/t/277410
[doublepost=1464800203][/doublepost]
Hellhammer said:
Some Intel slides also mentioned that 4K may require additional cooling on Core M chips, so Apple might have disabled it to avoid excessive throttling and other heat issues.
Click to expand...

For desktop use? Can't see it getting any hotter than playing a 3D game. Who knows... it's Apple :)
 
w0rd3r said:
Regarding the clamshell mode, I'll be able to test it in the upcoming weeks since I'll receive the KADI Port (with 2 USB-C).
https://www.kickstarter.com/projects/thekadiport/the-kadi-port-a-macbook-essential
So I'll use one with the charger and the other one with the DisplayPort adapter I mentioned earlier.

I still don't know if I'll be able to use every scaled resolution just like an iMac or a MacBook Pro. If anyone can tell me which resolutions are available (as I said, for me it only works @1080p HiDPI @60Hz. Others are not available or @30Hz) it would be great!
Click to expand...

Thanks for the tag!
 
rtr1985 said:
Any other monitors working besides Lenovo?
Click to expand...

I just patched my rMB running 10.11.5 and I'm up and running at a glorious 3440x1440 @ 60Hz on an LG 34UC98 connected through an Aukey USB-C hub with HDMI out.
 
in Cider said:
I just patched my rMB running 10.11.5 and I'm up and running at a glorious 3440x1440 @ 60Hz on an LG 34UC98 connected through an Aukey USB-C hub with HDMI out.
Click to expand...

34UC98 is not a 4K display though. I didn't think you needed a patch to run this display at 60Hz.
 
ctyrider said:
34UC98 is not a 4K display though. I didn't think you needed a patch to run this display at 60Hz.
Click to expand...

While its not 4k, the resolution is still too high for native 60Hz on my rMB. 50Hz is the max OS X will allow until after the patch.
[doublepost=1465144476][/doublepost]
Outrigger said:
its not a 4K display and you don't need a patch for it.
Click to expand...

I did need to patch to get to 60Hz on my rMB, otherwise the max I could get to work was 50Hz.
 
Last edited:
in Cider said:
While its not 4k, the resolution is still too high for native 60Hz on my rMB. 50Hz is the max OS X will allow until after the patch.
[doublepost=1465144476][/doublepost]

I did need to patch to get to 60Hz on my rMB, otherwise the max I could get to work was 50Hz.
Click to expand...

How usable is 4K at 50Hz?
 
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