# Mac Studio Issue with LG 43" Monitors (And Solution)



## Mike Greene (May 20, 2022)

My shiny new Mac Studio (Max) arrived last Friday (a month ahead of schedule) and I did the Migration Assistant thing so that this will be my _one_ computer, instead of going back and forth between two computers: a Mac Mini for email and personal stuff and Mac Pro for pro stuff. 64GB of RAM and 4TB of HD space ... one computer and no need for external drives ... so exciting!

But I starting noticing that the screen reaction was sluggish. Maybe 1/10 second lag behind my mouse moves. This was especially apparent if I quick-dragged a window (a Safari window, for instance) to the left or right, where I could hear my mouse drag on the desk a fraction of a second before seeing the move on my screen.

The same monitors (I have two identical LG 43UD79 monitors in this room) work perfectly with the 2013 Mac Pro and and my M1 Mac Mini, so this was weird that a newer computer would be so much slower. Just to be sure it wasn't bad cables or something, I even used the same HDMI cables into the same ports as I had been using with the Mac Mini and Pro. Same problem, with either LG monitor.

A few hours with Mac support (mostly reinstalling Monterrey and a bunch of other reset tricks) didn't help, so they sent me to the Genius Bar. I asked the guy if they had a monitor there, so I could _show_ him the screen lag. (My fear was that the tech guy wouldn't notice a 1/10 second lag and would think it's already fixed.) So he plugs in a little 22" monitor and ... the screen response is perfect! Nice and snappy. So I realized it must be my monitors, so I brought the Mac Studio back here.

I have a newer 43" LG (43UN700) in Studio B, so I thought maybe the electronics in that one might be more up to date and more compatible with the Mac Studio. That monitor includes a USB-C cable (mostly the same as Thunderbolt 4), so I tried that instead of HDMI. Success! So then I tried an HDMI cable, just to compare. Sluggish.

It turns out that with a Mac Studio plugged into these 43" LG monitors, if you use HDMI cables, then the refresh rate won't go higher than 30hz. With USB-C cables (I've also now tested USB-C to Display Port cables with the older LGs), you can do 60hz, and that makes all the difference. Note that with M1 Mac Mini, it was perfectly happy with HDMI cables and 60hz was no problem.

Seems weird that the difference between a 30hz refresh rate and 60hz would make that much of a difference, because the mathematic difference between 30hz and 60hz is only a half frame, yet the lag I was seeing was at least 2 or 3 frames. But I guess there's more going on behind the scenes than just the math we see on the surface. If nothing else, I appreciate frame rates more than I did before, and I wonder if this is what people are talking about when they say regular TVs won't be as fast as dedicated computer monitors.

I'm curious if this is just an LG issue, or whether all large monitors with have the same issue if HDMI cables are used. In the next day or two (before my 14 day return window closes), I'm going to take one of these monitors to Melrose Mac (where I bought the USB-C to Display Port cable) and see if their Mac Studio gives the same results, just to be sure this isn't a defect in my particular Mac. (Or if someone with a Mac Studio is in the Hollywood area and wants to stop by ... )


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## Mike Greene (May 25, 2022)

Followup - I took a 43" LG to Melrose Mac and plugged it into their Mac Studio using HDMI. Same problem, where the maximum refresh rate is 30hz. (Fine with 60hz using a USBC to Display port cable, though. Same as with my Mac Studio.) This is good news, since it means this is a Mac Studio issue, not just a defect with mine that would be reason for return before my 14 day window closes. I'm fine with USBC to DisplayPort, so I'm happy.

To reiterate - this issue may be unique to 43" LG monitors, since as I mentioned earlier, 60hz was fine with a different brand monitor, even through HDMI. So for many, if not most people, this won't be an issue at all. I'm just offering this experience in case someone else finds themselves in a similar situation.

One interesting thing FWIW - the woman who helped me told me that she believes the HDMI ports in Mac Studios (and I think she said in new laptops as well) are lower quality than the M1 Mac Minis, and people have complained about the downgrade. That would seem to be the case with me, where my M1 Mac Mini was perfectly fine with the same LGs through HDMI.


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## emasters (May 25, 2022)

Interesting... I've had my eye on the Mac Studio (or possibly the upcoming MB Pro), and use an external 27 inch 4k LG monitor. With my 2019 Intel MB Pro, HDMI to the LG works fine in 4k with a 60 hz refresh rate - no lag. Would be ashame if to save $, Apple down-graded those HDMI ports. Upgrades are always such fun. So how did Migration Assistant work? Clearly, one of the biggest challenges one faces moving to a new platform. Seems like I always end up rebuilding from scratch regardless. Would be curious if you were able to get most of your prior configuration to the new Mac Studio, without too much fiddling.


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## AlphaCen (May 25, 2022)

HDMI on recent Macs is a minefield, best to go with USB-C or USB-C to DP. There are countless problems both on recent Intel Macs and on M1/Pro/Max/Ultra machines, EDIDs are wrong, resolution or refresh rate is wrong or Mac sets colour space as YCbCr instead of RGB because it thinks that HDMI is only for TVs. Macrumors forum has several threads about it.


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## Dewdman42 (May 26, 2022)

Thanks for the detailed report @Mike Greene


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## marclawsonmusic (May 26, 2022)

Hi Mike, I heard of a similar issue from this guy on YouTube:


Putting his experience and yours together, it sounds like it's related to the HDMI port - something about it being version 2.0? So, it might not be LG-specific.

Thanks for sharing


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## Zedcars (May 26, 2022)

Mike Greene said:


> My shiny new Mac Studio (Max) arrived last Friday (a month ahead of schedule) and I did the Migration Assistant thing so that this will be my _one_ computer, instead of going back and forth between two computers: a Mac Mini for email and personal stuff and Mac Pro for pro stuff. 64GB of RAM and 4TB of HD space ... one computer and no need for external drives ... so exciting!
> 
> But I starting noticing that the screen reaction was sluggish. Maybe 1/10 second lag behind my mouse moves. This was especially apparent if I quick-dragged a window (a Safari window, for instance) to the left or right, where I could hear my mouse drag on the desk a fraction of a second before seeing the move on my screen.
> 
> ...


I have exactly the same setup of monitor and Mac Studio. I too gave up on HDMI and went with the Display Port instead. Much better!


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## Mike Greene (May 26, 2022)

emasters said:


> So how did Migration Assistant work? Clearly, one of the biggest challenges one faces moving to a new platform. Seems like I always end up rebuilding from scratch regardless. Would be curious if you were able to get most of your prior configuration to the new Mac Studio, without too much fiddling.


I used Migration Assistant (or whatever it's called when you install everything from a Time Machine drive) and it seemed to work pretty well. All my mail was there, which was the main thing I cared about, since it goes back over a decade over multiple accounts, and I need all that just like I left it on the Mac Mini.

Safari worked, and I think I must have tested Kontakt, too, because I had to reinstall Native Access. Weird that it apparently didn't survive the transfer, but those sorts of apps are pretty easy. All my libraries are saved in multiple places, so even if Migration Assistant screws those up, I have lots of backups, so there shouldn't be any need for huge downloads.

That's pretty much the extent of what I tested, since once I noticed the lag, I focused on that, and the "fix" that the first tech support guy had me do was to reformat the drive and reinstall Monterrey. 

Fingers crossed that Migration Assistant goes well the second time, although with NAMM coming up, I think I'll wait until after I get back.  



marclawsonmusic said:


> Hi Mike, I heard of a similar issue from this guy on YouTube:
> 
> 
> Putting his experience and yours together, it sounds like it's related to the HDMI port - something about it being version 2.0? So, it might not be LG-specific.
> ...



It looks like you're right that it isn't LG specific. What's frustrating is that all three Apple guys (two tech support guys on the phone and one guy at the Genius Bar) knew nothing about any of this. This was a lot of hours spent, when all I really needed was for one of them to tell me to use the Thunderbolt port.


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## Dewdman42 (May 26, 2022)

We need to find out more specifically what the HDMI incompatibility is that causes some kind of conversion processing to slow everything down. I guess this will come out eventually as more people come across it and solve the issue on the hardcore Mac forums. I don't expect the GeniusBar to be very "genius" about it anytime soon frankly. 

There are a number of different HDMI versions and I suspect this is some kind of HDMI version incompatibility that is forcing M1 built in GPU to convert something on the fly.

I once had a lot of problems with a couple apps, including DP...they were slowed down to ridiculous slugglish levels and I couldn't figure out why. Eventually I figured out it was because I was trying to use a custom color profile in MacOS display preferences. Apparently that re-calculation of color values was causing a lot of unnecessary calculations to happen. Turned off the color profile; and everything sped up to normal. That's a separate issue from HDMI, but just pointing out that if the system has to recalculate anything...there could be lag.

Also these kinds of issues are usually amplified by larger monitors with more pixels and especially when hiDPI retina modes are being used.


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## Nimrod7 (May 26, 2022)

I also have a Mac Pro connected with HDMI and is outputting 4K 60hz as normal. 
The Mac Studio also supports HDMI 2.0 which is 4K 60hz, and I am wondering if the cable is lower spec. 

Did you had a chance to try a different cable that is HDMI 2.0 or above? 

An the story with HDMI cables is ...interesting...


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## Dewdman42 (May 26, 2022)

in my opinion, FWIW, a different frame rate would not cause lag (directly). A lower frame rate would provided a degraded video experience, but not lag. Less frames per second should actually result in LESS lag....if that were the case... less frames to process per second. But at 30hz you might notice the screen flicker... for example. But again...if anything related to frame rates causes something in the M1 to "recalculate" anything...that recalculation could create lag.


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## Michael Antrum (May 26, 2022)

My Studio (hopefully) will be arriving tomorrow. I was planning to connect it t my 32" 4k Samsung display via HDMI.....

I'll let you know what happens, but I won't be doing a 'Migration Assistant' from my 2009 Mac Pro....


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## Mike Greene (May 29, 2022)

Dewdman42 said:


> in my opinion, FWIW, a different frame rate would not cause lag (directly). A lower frame rate would provided a degraded video experience, but not lag. Less frames per second should actually result in LESS lag....if that were the case... less frames to process per second. But at 30hz you might notice the screen flicker... for example. But again...if anything related to frame rates causes something in the M1 to "recalculate" anything...that recalculation could create lag.


I would have thought the same thing, but even with my Mac Mini, which happily allows both 30hz and 60hz, there is a noticeable lag at 30hz, but not at 60hz. It doesn't make any sense to me, but Nimrod's cable video (which is scary!) could be a factor, plus I don't know whether my cables are 2.0, which I suppose means they probably aren't.


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## Dewdman42 (May 29, 2022)

my argument woiuld be that the 30hz is causing some kind of conversion to take place. Think of the 30hz like "less dense video". Its a lower sample rate. 30hz on its own does not require more resources, it requires less. But...if a conversion happens because the Studio can't handle 30 hz video directly on its own..that would cause lag. Or it might just be a coincidence that its 30hz and the real problem is some other aspect of HDMI versions being incompatible enough that some conversion process has to take place.


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## dterry (May 29, 2022)

I had the same issue with a Mac Mini M1 and 27" 4k display - 4k was locked to 30Hz, despite the M1s supporting 4k at 60Hz. This is a quirk (bug) in the new Macs/OSX (and some previous Macs to apparently), not an HDMI issue. You have to manually force the Mac M1 to see a 60Hz option in Display settings. Even after this fix, the Mini reverted back to 30Hz after an OS update, so at least in this case, it is an OSX problem.

I'll post back Tuesday when back in the studio to see if I can recreate and post the steps to restore 60Hz as an option. I may have a link saved to the solution I found online.


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