Hi Rosmoke, thank you for joining our forum! 
Have you been in contact with our support team already on this issue? 
If not, pls send a brief mail detailing your setup to [email protected] so our colleagues can assist with troubleshooting. Thanks!

I’ve just sent an email now even though I think it would be more useful for everybody we could figure it out in this forum. I’m sure more people will benefit from this.

This is my email:

Hi,

I’m trying to get 4k@60hz on my LG UF770V, I’m using a CAC-1170 adaptor (mini dp 1.2 to hdmi 2.0), hdmi cable 18gbps 2.0 (have tried 4 of them), the last hdmi cable actually allows me select 4k@60hz without the need of adding a custom resolution in switchresx.

On the back of my tv it’s written 4k@60hz, in the menu I enabled and disabled Lg Ultra Hd Deep Color, port 1 supports 4k@60hz (4:4:4, 4:2:2, 4:2:0).

When I select 3840 x 2160, 60 Hz (NTSC) HiDPI or the one without HiDPI the TV works ok, but shows 30hz, even in tv menu it shows 4k@30hz.

In http://www.testufo.com I get 60hz, in About This Mac / System Report… / Graphics/Displays / it shows the resolution : 3840 x 2160 @ 60 Hz.

I have also updated the firmware for this adaptor with ps176b0_0x07.0x00.0x23_encryt_bank12.hex (you have no idea how hard it was to find a computer with a dedicated gpu, windows, mini dp port).

I have tried it on 3 macbooks (Late 2013 rMBP 15”, Mid 2014 rMBP 13”, Mid 2015 rMBP 15″), two tv’s (LG UF770V (my tv), LG UF850V (friend’s tv)).

The third cable which I have bought is : http://www.ebay.ie/itm/391324200976?_trksid=p2057872.m2749.l2649&var=660570922231&ssPageName=STRK%3AMEBIDX%3AIT

This is the last hdmi cable which I have bought http://www.adverts.ie/cables/gold-plated-2m-high-speed-hdmi-2-0-cable-full-hd-1080p-2160p-4k-2k-3d-for-ps3-lcd-dvd-hdtv/9152841?notification=75e0c281cb8392a6bd3d3f18ec045ac1-1462058125#comment_68183533

<p class=”p1″>Basically I can choose 4k@60hz but in fact the tv displays 4k@30hz, even though the laptop informs me that the tv displays 4k@60hz.

What else can I do ?

Thanks,

Daniel Asofiei.

You haven’t said if your MacBook is 13″ or 15″, be aware that the 13″ one is not capable of outputting 4k@60hz, my wife has the 13″ Mid 2014 and it doesn’t work.

It’s 15″, and everything else in my setup is capable.

Hi kphs, which graphics solution is in your MacBook?

It’s a Mid 2014 MacBook Pro 15″ with an NVIDA GeForce GT 750M 2GB. I also have a late 2013 MBP 15″ with the same video card, both of which should be able to do 4k@60hz according to Apple https://support.apple.com/en-us/HT206587

kphs, I have it running on a late 2013 MBP Retina 15″ and a mid 2015 MBP Retina 15″, if you are sure that you tv has a hdmi port capable of 4k@60hz and you also used switchresx with the settings from above, you should change your hdmi cable till you get one capable of 4k@60hz, I had tried with 3 cables before I finally got one capable. Choose one thick and with a textile protective coating. Hope this helps.

For any (future proof) 4K HDMI experience it’s worthwhile to buy a Premium Certified HDMI cable like our CAC-1310. These are tested to ensure they support the full 18Gbps bandwidth needed for 4K 60Hz while remaining affordable. 

http://www.hdmi.org/manufacturer/premiumcable/Premium_HDMI_Cable_Certification_Program.aspx 

Ok, I finally resolved the issue. It was just the same old SwithResX bug which requires me to create a new user profile and create a custom res as that user and installed it. I didn’t have much expectation when I decided to take that route since I had no problem saving custom res. It just that SwitchResX didn’t let me install it. And also talking to SwitchResX team wasn’t that helpful. They just basically said either I have incompatible TV or a broken adapter. When I created a custom res and installed it as a new user, it let me install the custom res with no problem.