Display and Adapter Questions

[iAdamator]

Recently got the Mac Studio as my first Mac. Got some Display related questions I’m hoping to get some help with.

I have 2 1440p Monitors, Dell 2721DGF’s. I want to hook them both up. I can use HDMI for one of the connections but for the other I figure a USB-C to HDMI would be the way to go right?

A few questions on that. I hope these don’t come across as dumb. As I said, I am new to Mac.

1. If I have 1 monitor plugged in HDMI to HDMI and the other plugged in via USB-C to HDMI, would there be any perceivable difference in quality on the 2 monitors? (Or would I want to do some kind of USB-C to HDMI for BOTH Monitors?

2. is USB-C and Thunderbolt the same thing? Or to put it another way, do I want a USB-C to HDMI adapter/cable or a Thunderbolt to HDMI adapter/cable?

3. Am I better off with a USB-C to HDMI cable or just getting an adapter and then using a regular HDMI cable?

4. These monitors can do 165 Hz depending on the connection, but I would be happy with 120 Or so. Really silly question here and forgive my ignorance but does having a high hz monitor on a Mac in any way approximate ProMotion?

Thanks

 

[joevt]

I have 2 1440p Monitors, Dell 2721DGF’s. I want to hook them both up. I can use HDMI for one of the connections but for the other I figure a USB-C to HDMI would be the way to go right?

DisplayPort is better. HDMI port can only connect one display, so you'll need to connect the other to a Thunderbolt port. In that case, use a Thunderbolt to Dual DisplayPort adapter to connect both displays to the same Thunderbolt port. Or you can use a Thunderbolt dock or hub.

1. If I have 1 monitor plugged in HDMI to HDMI and the other plugged in via USB-C to HDMI, would there be any perceivable difference in quality on the 2 monitors?

No.

2. is USB-C and Thunderbolt the same thing? Or to put it another way, do I want a USB-C to HDMI adapter/cable or a Thunderbolt to HDMI adapter/cable?

They are not the same. Thunderbolt can do USB-C. USB-C (non-Thunderbolt port) cannot do Thunderbolt.

USB-C is limited to one display in macOS. Thunderbolt can connect two displays with a Thunderbolt dock or hub or adapter.

USB-C limit is 25.92 Gbps DisplayPort, or 19.4 Gbps USB 3.2 gen 2x2 (not supported by macOS), or 9.7 Gbps USB 3.1 gen 2 + 12.96 Gbps DisplayPort. The signals are separate (decreasing bandwidth used by DisplayPort does not allow higher bandwidth for other signals).

Thunderbolt limit is 40 Gbps. The signal mixes USB 3.1 gen 2 and DisplayPort and PCIe together. It can do up to two separate DisplayPort signals (up to 17.28+17.28 Gbps or 8.64+25.92 Gbps).

3. Am I better off with a USB-C to HDMI cable or just getting an adapter and then using a regular HDMI cable?

An adapter may be less expensive and more useful.

4. These monitors can do 165 Hz depending on the connection, but I would be happy with 120 Or so. Really silly question here and forgive my ignorance but does having a high hz monitor on a Mac in any way approximate ProMotion?

Maybe. I don't know the details of which Macs/displays get the variable refresh rate feature.
https://forums.macrumors.com/threads/variable-refresh-rate-freesync-gsync-flicker.2320463/
https://support.apple.com/en-us/HT212232

 

[mcnallym]

1. Should be be same, however personally prefer displayport to hdmi for connectivity. I have a usb-c to displayport that supposedly supports 8k waiting for when my studio turns up.

2. No USB-C is strictly a physical interface spec. Thunderbolt 3 and 4 use USB-C interface whereas TB and TB2 used the same physical interface as mini-display port. USB 3.x may also use the USB-C interface as an aternative to USB-A. For instance my Drobo5c has a USB-C interface but only does 5Gbps whereas other USB-C devices offer upto 20Gbs if using USB 3.2 gen 2x2

If you buy a Studio with MAX SoC then the two ports on the front are USB-C interfaces that support USB protocols, but not Thunderbolt. The rear USB-C ports however support Thunderbolt as well as USB devices.

USB 3.2 standard gets new, even more confusing names ahead of its mainstream debut

The new spec promises up to 20Gbps speeds, but the names are more complicated than ever

www.theverge.com

Good article around USB standards and al also covers USB interfaces.

USB-C is however purely a physical spec not what can run over it.

USB 3.2 gen1 (5Gbps)
USB 3.2 gen2 (10Gbps)
USB 3.2 gen2x2 (20Gbps)
TB3 (40Gbps)
TB4 (40Gbps)

All can be using a USB-C physical interface.

Apple really do not help by saying that the Studio with Max has 2 front USB-C interfaces whereas Studio with Ultra has TB4 ports.

Both have USB-C ports as that is the physical port, Max has USB 3.2 Gen2 USB ports and Ultra has TB4 ports.

3. Should not make a difference.

4. ProMotion is more then just high refresh rate but also adaptive refresh rate.

Dual Display Adapters - SONNETTECH

Thunderbolt and DisplayLink adapters with dual DisplayPort or HDMI ports. Connect 4K displays to M1 and M2 Macs and computers with Thunderbolt 4 or 3 ports.

www.sonnettech.com

If bothered then get one of these and then connect both monitors to it, and can select HDMI or DP version.
I prefer DP personally but is personal preference as my monitor supports higher res over DP.

 

[Amethyst1]

If bothered then get one of these and then connect both monitors to it, and can select HDMI or DP version.

In this case, it's important to get a Thunderbolt version, not a DisplayLink one.

 

[iAdamator]

DisplayPort is better. HDMI port can only connect one display, so you'll need to connect the other to a Thunderbolt port. In that case, use a Thunderbolt to Dual DisplayPort adapter to connect both displays to the same Thunderbolt port. Or you can use a Thunderbolt dock or hub.


No.


They are not the same. Thunderbolt can do USB-C. USB-C (non-Thunderbolt port) cannot do Thunderbolt.

USB-C is limited to one display in macOS. Thunderbolt can connect two displays with a Thunderbolt dock or hub or adapter.

USB-C limit is 25.92 Gbps DisplayPort, or 19.4 Gbps USB 3.2 gen 2x2 (not supported by macOS), or 9.7 Gbps USB 3.1 gen 2 + 12.96 Gbps DisplayPort. The signals are separate (decreasing bandwidth used by DisplayPort does not allow higher bandwidth for other signals).

Thunderbolt limit is 40 Gbps. The signal mixes USB 3.1 gen 2 and DisplayPort and PCIe together. It can do up to two separate DisplayPort signals (up to 17.28+17.28 Gbps or 8.64+25.92 Gbps).


An adapter may be less expensive and more useful.


Maybe. I don't know the details of which Macs/displays get the variable refresh rate feature.
https://forums.macrumors.com/threads/variable-refresh-rate-freesync-gsync-flicker.2320463/
https://support.apple.com/en-us/HT212232

Appreciate the info, thank you. I want to keep the cost down so I don't think I'll go with a dock. I think a dock would be a bit much with a Mac Studio and all it's ports.

Just for a bit of clarity, I only have HDMI ports available on my monitors. The DisplayPorts are being used for my PC. Since I can use the included HDMI port for one monitor, I was just wondering what option was best for my other monitor. I know I would need to use an adapter or cable with HDMI on one end, and USB-C/Thunderbolt on the other.

 

[iAdamator]

1. Should be be same, however personally prefer displayport to hdmi for connectivity. I have a usb-c to displayport that supposedly supports 8k waiting for when my studio turns up.

2. No USB-C is strictly a physical interface spec. Thunderbolt 3 and 4 use USB-C interface whereas TB and TB2 used the same physical interface as mini-display port. USB 3.x may also use the USB-C interface as an aternative to USB-A. For instance my Drobo5c has a USB-C interface but only does 5Gbps whereas other USB-C devices offer upto 20Gbs if using USB 3.2 gen 2x2

If you buy a Studio with MAX SoC then the two ports on the front are USB-C interfaces that support USB protocols, but not Thunderbolt. The rear USB-C ports however support Thunderbolt as well as USB devices.

USB 3.2 standard gets new, even more confusing names ahead of its mainstream debut

The new spec promises up to 20Gbps speeds, but the names are more complicated than ever

www.theverge.com

Good article around USB standards and al also covers USB interfaces.

USB-C is however purely a physical spec not what can run over it.

USB 3.2 gen1 (5Gbps)
USB 3.2 gen2 (10Gbps)
USB 3.2 gen2x2 (20Gbps)
TB3 (40Gbps)
TB4 (40Gbps)

All can be using a USB-C physical interface.

Apple really do not help by saying that the Studio with Max has 2 front USB-C interfaces whereas Studio with Ultra has TB4 ports.

Both have USB-C ports as that is the physical port, Max has USB 3.2 Gen2 USB ports and Ultra has TB4 ports.

3. Should not make a difference.

4. ProMotion is more then just high refresh rate but also adaptive refresh rate.

Dual Display Adapters - SONNETTECH

Thunderbolt and DisplayLink adapters with dual DisplayPort or HDMI ports. Connect 4K displays to M1 and M2 Macs and computers with Thunderbolt 4 or 3 ports.

www.sonnettech.com

If bothered then get one of these and then connect both monitors to it, and can select HDMI or DP version.
I prefer DP personally but is personal preference as my monitor supports higher res over DP.

Thank you. This really helped me understand what Thunderbolt is and how it's just using the same physical plug as USB-C. Having never had a Mac, I never really knew much about Thunderbolt so this was interesting.

I do have an Max Mac Studio. I'm just looking at how to plug in my second monitor. The monitor only has an available HDMI port. It sounds like a simple Thunderbolt to HDMI adapter is what I'd likely want.

 

[iAdamator]

I have been giving this more thought. Even though my Windows PC is currently using the DP plugs on my Monitors, I COULD switch it to use HDMI and free up the DP. My question is...would I gain anything By giving the DP to my Mac? I did a quick test on my Windows PC and switch one monitor to HDMI. It looked fine and I could still select a high fresh rate, but my nVidia card no longer recognized it as “G SYNC compatible.” That’s about the only difference I saw.

 

[joevt]

I have been giving this more thought. Even though my Windows PC is currently using the DP plugs on my Monitors, I COULD switch it to use HDMI and free up the DP. My question is...would I gain anything By giving the DP to my Mac? I did a quick test on my Windows PC and switch one monitor to HDMI. It looked fine and I could still select a high fresh rate, but my nVidia card no longer recognized it as “G SYNC compatible.” That’s about the only difference I saw.

Does your Mac support VRR using HDMI or DP to the display? I don't know.
https://support.apple.com/en-us/HT212232
I suppose you don't care about the difference between 144Hz 8bpc HDMI and 165Hz 8bpc DisplayPort.
HDR requires 10bpc which means 115Hz for HDMI and 137Hz for DisplayPort but you have a Mac Studio and cannot create custom timings so you get only what Apple gives. The display only has HDR400 so maybe you won't use it. Maybe macOS will use chroma sub sampling (4:2:2 or 4:2:0) to get max refresh with 10bpc. I don't know how to test for that on an M1 Mac.

 

[iAdamator]

Does your Mac support VRR using HDMI or DP to the display? I don't know.
https://support.apple.com/en-us/HT212232
I suppose you don't care about the difference between 144Hz 8bpc HDMI and 165Hz 8bpc DisplayPort.
HDR requires 10bpc which means 115Hz for HDMI and 137Hz for DisplayPort but you have a Mac Studio and cannot create custom timings so you get only what Apple gives. The display only has HDR400 so maybe you won't use it. Maybe macOS will use chroma sub sampling (4:2:2 or 4:2:0) to get max refresh with 10bpc. I don't know how to test for that on an M1 Mac.

Thanks for the info. I'm sorry I should have mentioned previously that my original post is out of date. I returned the Studio and decided to give a MacBook a try instead. Specifically, a Base Macbook Pro 14. It remains to be seen how I will use it as far as external monitors, as the main reason I wanted to try one was due to the awesome display it has that I can use to edit HDR videos. Should I still want to use my external monitors I can of course use the HDMI on the laptop for one, but if I were to want to use both my externals, I'd need an adapter.

Regarding your question, I would be fine with 144 HZ or 165 HZ. Heck I might even just bring any external monitor down to 120 just for consistency with the built in display.

Is bpc referring to 8 and 10 bit? I hadnt seen it referrec to as bpc before.

 

[joevt]

Is bpc referring to 8 and 10 bit? I hadnt seen it referrec to as bpc before.

bpc = bits per component. Three components: R, G, B or Y, Cb, Cr. So 8bpc and 10bpc are 24bpp and 30bpp (bits per pixel).

If a display supports DSC, macOS usually uses 12bpc (36 bpp) which is compressed to 12bpp using DSC. Change 12bpp using the dscTargetBPP setting #172

EDIT (Oct 3, 2024):
Turns out that the dscTargetBPP preference can only be changed if the Apple Internal SIP bit is set, and that bit cannot be set by csrutil. I don't know how to change that bit.

My WhateverGreen fork (Intel Macs only) has a new patch to change dscTargetBPP (add a boot-arg dscbpp=8 - for Catalina and later). If you're using Open Core or OCLP, then you can replace Lilu and WhateverGreen with my versions. If you use any other Lilu based kexts then they need to be recompiled using the headers from my Lilu.kext. That patch, in conjunction with the CheckTimingWithRange patch (add a boot-arg -cdfon - For Tiger and later), can enable 4K240 and beyond on Intel Macs with a GPU that supports DSC (tested with 6800XT and Sequoia). DP to HDMI adapters are not tested.

I think Apple Silicon Macs automatically support DSC with values ≤ 12 (4K240 tested on M3 with Sequoia).