DP/USB-C/Thunderbolt to HDMI 2.1 4k@120hz RGB4:4:4 10b HDR with Apple Silicon M1-M4 now possible !

[phone5g]

Hi all I am looking to confirm I am using the optimal settings on my new display setup. I am currently using:

-2021 14" M1 Pro - Sequoia 15.2

-LG C4 42"

-Cable Matters 48Gbps USB C to HDMI 2.1 Adapter for macOS​

-Anker HDMI 2.1 Cable​

-LG DualUp

-USB C Cable​

I currently am using BetterDisplay to run the C4 at 3008x1692 HiDPI 120Hz and the DualUp at 2048x2304 HiDPI. I am wondering what the optimal settings are for the C4 both in BetterDisplay and on the tv. 3008x1692 seems to look a little sharper than 4k, is that a scaling thing? Should HDR be on and does that require Betterdisplay pro?

Thanks!

 

[alaskatroll]

Hi all I am looking to confirm I am using the optimal settings on my new display setup. I am currently using:

-2021 14" M1 Pro - Sequoia 15.2

-LG C4 42"

-Cable Matters 48Gbps USB C to HDMI 2.1 Adapter for macOS​

-Anker HDMI 2.1 Cable​

-LG DualUp

-USB C Cable​

I currently am using BetterDisplay to run the C4 at 3008x1692 HiDPI 120Hz and the DualUp at 2048x2304 HiDPI. I am wondering what the optimal settings are for the C4 both in BetterDisplay and on the tv. 3008x1692 seems to look a little sharper than 4k, is that a scaling thing? Should HDR be on and does that require Betterdisplay pro?

Thanks!

See the third warning in the original post - because you’re on M1 and Sonoma 15.2, your HDR stops working when you set resolution to 4k+ in HiDPI mode. Could be why it looks worse (why I set up my M1 pro with ventura). It’s also possible that you simply prefer the look of the antialiasing involved with upscaling the slightly lower resolution to the 4k screen. Disable HDR and closely compare 4k to 3008x1692 particularly around text. If 4k looks better and you want HDR at 4k you have to roll back MacOS, let me know if you need help with that as it’s a huge pain (see my post on prev page)

 

[kristof461]

This is so ridiculous. Typical Apple. Making thing complicated.
I have only one DP in my gaming monitor. I wanted to use it for PC but nooooo. Apple prefers DP so I can get 144hz in 1440p or 95Hz in 1690 but via HDMI only 60Hz. Why?
I don’t even have windows laptop with proper usb c port

 

[phone5g]

See the third warning in the original post - because you’re on M1 and Sonoma 15.2, your HDR stops working when you set resolution to 4k+ in HiDPI mode. Could be why it looks worse (why I set up my M1 pro with ventura). It’s also possible that you simply prefer the look of the antialiasing involved with upscaling the slightly lower resolution to the 4k screen. Disable HDR and closely compare 4k to 3008x1692 particularly around text. If 4k looks better and you want HDR at 4k you have to roll back MacOS, let me know if you need help with that as it’s a huge pain (see my post on prev page)

Gotcha appreciate the help! Did some testing and now for some reason every resolution under 4k is not properly fitting on the screen. Its a work computer so don't think I want to deal with downgrading the OS at the moment. Going to stick with 4K HiDPI 60hz and no HDR for now and hope for a bug fix soon.

 

[kristof461]

I just received my adapter. It says 201388 with A but software shows newer VMM7100 chip.

 

[awer25]

Anyone with an M1 Max/Ultra update to 15.3 and have new issues running these high resolutions and refresh rates?

 

[AppelGeenyus]

Wow still none of these problems fixed in 15.3, MacOS officially stinks. So much time has passed and we still can't get basic monitor functionality back, wtf is Apple doing 🤬

 

[awer25]

Wow still none of these problems fixed in 15.3, MacOS officially stinks. So much time has passed and we still can't get basic monitor functionality back, wtf is Apple doing 🤬

Sad to hear this. I'll hold off a while longer on updating. On 15.2 and an M1 Ultra, I finally got 7680x2160@120Hz and I don't want to break it. The M4/M5 Mac Studios can't come fast enough lol.

 

[ade2]

Hello thread

Writing to let you all know that flashing a jCreate JCA157-N USB-C to HDMI dongle is WORKING. It is a VMM7100 device. I used cable matters firmware file, but flashed it with VmmHidTool from windows store manually.

Unfortunately, no matter how I tried, I could not dump the previous stock firmware. The firmware file ends up being all zeroes and is only 320kb (as opposed to the cable matters files are all 1024kb)

 

[RdWing]

Even at 120 Hz, I am unable to get HiDPI for 3840x1600. Doesn't matter over HDMI, DP, nothing. Currently on 15.3 with an M4 Max.

 

[awer25]

Anyone with an M1 Max/Ultra update to 15.3 and have new issues running these high resolutions and refresh rates?

I ended up updating to 15.3, first making sure BetterDisplay and SwitchRes were up to date. I didn't have any new issues and the monitor is still at 120Hz.

 

[ExtremeEdition]

@Zorast Where can i find the latest firmware for a VMM7100 USB-C to HDMI 2.1 cable? I read that you have a 7.02.130 firmware available, but I couldn't find it. Thanks in advance

 

[ultratiem]

@Zorast Where can i find the latest firmware for a VMM7100 USB-C to HDMI 2.1 cable? I read that you have a 7.02.130 firmware available, but I couldn't find it. Thanks in advance

Cable Matters Firmware Update Tool [4k@120hz on macOS] - Cable Matters Knowledge Base

 

[Zorast]

I ended up updating to 15.3, first making sure BetterDisplay and SwitchRes were up to date. I didn't have any new issues and the monitor is still at 120Hz.

Fine, thanks! Are u on HiDPI 4k@120hz ?

EDIT:
@waydabber just confirm to me, that there is no conflict reported to him. So i will also update to 15.3.1 tonight.

 

[Zorast]

Sad to hear this. I'll hold off a while longer on updating. On 15.2 and an M1 Ultra, I finally got 7680x2160@120Hz and I don't want to break it. The M4/M5 Mac Studios can't come fast enough lol.

Yeah and apple show us, still with TB5 they limit it to 4k@60hz !

 

[awer25]

Fine, thanks! Are u on HiDPI 4k@120hz ?

EDIT:
@waydabber just confirm to me, that there is no conflict reported to him. So i will also update to 15.3.1 tonight.

Not HiDPI. I'm using a 7680x2160 monitor (Samsung G9 57") so MacOS sees two 4K@120 monitors side by side (one via USB-C to DP cable, one via flashed HDMI dongle). I haven't tried the HiDPI hack, but at the native resolution text looks super sharp. I may play around with it later to compare with HiDPI, if it's possible with this setup.

Edit: I got HiDPI enabled using your post here, and am now on 4k@120 HiDPI for both sides of the monitor (confirmed with testufo.com). It does look slightly better in HiDPI so I'll keep it here.

 

[Zorast]

Not HiDPI. I'm using a 7680x2160 monitor (Samsung G9 57") so MacOS sees two 4K@120 monitors side by side (one via USB-C to DP cable, one via flashed HDMI dongle). I haven't tried the HiDPI hack, but at the native resolution text looks super sharp. I may play around with it later to compare with HiDPI, if it's possible with this setup.

Edit: I got HiDPI enabled using your post here, and am now on 4k@120 HiDPI for both sides of the monitor (confirmed with testufo.com). It does look slightly better in HiDPI so I'll keep it here.

Really nice! Iam also now on 15.3.1 and on my side 4k@120hz HiDPI works like before - can be enabled with unexposed frequencies.


And yeah, HiDPI looks also in nativ resolution better because apple has less good font smoothing when the pixel density is less than about 200ppi.

 

[thewongster]

For anybody scouring this thread for clues (as I was doing a few days ago), I just received my MBP 16" M4 Max, connected to an LG C4 via a Cable Matters 201310 adapter (the one with HDMI, Ethernet, 2 USB-A and and power pass-through) and a Cable Matters 48Gpbs 2.1 HDMI cable (2m). Mac OS Sequoia 15.2.

I can confirm that before flashing the custom firmware, options in the resolution panels were severely limited. I then immediately flashed the one from the knowledge base (while the one in the OP works and I'm sure it's safe, the procedure from the official source seems safer and more streamlined), this particular model as already described requires a Windows PC with USB-C and DP Alt mode. It updated it from 07.02.100 to 07.02.105.

Everything now behaves exactly like using the internal HDMI 2.1 port. Resolutions up to 3840x2160 with HiDPI and HDR at 120hz, 4:4:4 passthrough enabled. I didn't even need any workaround from the OP (maybe it was needed for earlier M processors?) everything works straight out of the box. Can also set brightness directly with the Apple keys, and sound volume too (that's why I chose that particular adapter, to plug in a USB audio dongle which becomes the audio out interface).

I'm still baffled as @kasakka a few post earlier on how scaled resolutions are kinda funky. 1920x1080 and anything up to 2304x1296 works perfectly, but as soon as I step in 2560x1440 and beyond something needs to be sacrificed at every step, either HDR or refresh rate. At 3840x2160 everything comes back (HiDPI, HDR and 120hz). Tried messing about on BetterDisplay but ultimately decided to settle at 2560x1440 100hz.

Can anybody explain what is happening to these scaled resolutions? I thought Mac OS was still sending the same UHD signal out regardless of scaling, which happens on the Mac (like in my case rendering 2880p and then scaling down to 2160p and sending THAT to HDMI), but apparently if bandwidth plays a role the scaling process is not completely happening on the Mac?

Hey! Just about to receive my first Mac in about a decade (14" MBP M4 base) and I fell down the rabbit hole as I realized hooking up my current setup might be a little more difficult then expected... Looking at your post though I feel like we have halfway a similar setup in that I have an LG C2 4k120hz via HDMI 2.1 with a PC laptop + an LG DualUp 28MQ780 (2560 x 2880) 60hz via USB-C with 90W PD. Currently on the windows Laptop they both are connected separately through the HDMI 2.1 port and the USB-C port and work in extended mode.

I was also looking at the Cable Matters 201310 adapter to try and consolidate my connections into a 1-cable solution and I was thinking that if I flashed it this would be the perfect 1-cable solution at a fairly affordable price. Would you be able to confirm if you can run a second monitor at 60hz through the USB-C port on that adaptor in extended mode with the HDMI 2.1 port on that same adaptor?

Worst case scenario I assume I can do a 2-cable solution with 1 x HDMI 2.1 directly to MBP + 1 x USB-C for second monitor + power delivery.

Actually would anyone be able to confirm my plan/roadmap?