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KRSogaard

macrumors newbie
Original poster
Jan 3, 2024
3
1
My awesome wife gifted me a MacBook Pro M3 Max for Christmas, an impressive laptop with excellent battery life and performance. However, I'm having significant issues with external displays. As my workflow relies heavily on an external display (over 80%), this has become a major problem.

The main issue is that most displays appear fuzzy and blurry. Searching online for solutions has led to frustrating responses like:

  • "I don't have that problem." (Perhaps those respondents need to visit an optometrist. 🙂)
  • "Check your cable."
  • "Increase the scaling." Unfortunately, these haven't been helpful in resolving my issue.
To provide some context, here’s a list of my devices and monitors:

  • Computers:
    • Gaming Desktop with a 3070
    • 2020 Razer Laptop with a 2070 Super
    • 2022 Razer Laptop with a 3070
    • MacBook Pro 2019 (Intel)
    • MacBook Pro M3 Max
  • Monitors:
    • LG C2 (HDMI - 4k 42", my home setup)
    • CRG9 (5120x1440 49" Super-Ultrawide, my office setup)
All my computers, except the M3 Max, work perfectly with these monitors. On the LG C2, I use 125% scaling and 100% scaling on the CRG9, without any blurriness or text fuzziness.

However, with the MacBook Pro M3 Max:

  • On the LG C2, there is significant blurriness at every scaling except for the native 4k scaling.
  • On the CRG9, everything is blurry no matter the scaling, and the colors are extremely washed out.
I can somewhat tolerate the LG C2 at 4k scaling, but the CRG9 is completely useless. Is there a solution, or has Apple deprioritized support for external displays? I'm contemplating returning the MacBook due to this issue. As a programmer, clear, readable text is essential.

Additionally:

  • On my LG C2, I can use 120Hz with HDR at native 4k resolution.
  • On other scalings [3200x1800, 2560x1440], I can only choose between HDR or 60Hz.
  • Interestingly, at the 1080x1920 scaling, I can again achieve 120Hz with HDR.
Video of the settings:

I wanted to ask for advice or solutions here before deciding on returning the MacBook.
 

amasondev

macrumors newbie
Jan 3, 2024
1
0
The way that scaling works on macOS is if you want a non-integer scaling factor (1.5x as opposed to 2x), the operating system's backbuffer is double the target resolution. For example, when you click the option for 3200x1600, the OS renders at 6400x3200 with 2x scaling, then scales that down to the native resolution (3840x2160 in your case) using bilinear sampling. Yes, it's bad. It also means that an HDR buffer at that 6400x3200 resolution is probably too large for the system to handle. I don't know how much memory your system has, or if that even makes a difference. You could look into alternative display handling apps such as https://github.com/waydabber/BetterDisplay and see if you get the results you're looking for. Or just accept the 1920x1080 scaled resolution.
 

G5isAlive

Contributor
Aug 28, 2003
2,861
4,911
I have two monitors hooked up to my MBP M3 Max , the Apple Studio Display and the LG HDR 4k, and both work fine. So I don't have your problems (and saw my optometrist a month ago). I say that to say, that external monitors can work with the M3.

I have noticed the LG seems to be picky about what cord I hook it up with, but right now I am running it fine with a high quality HDMI cable. I know you have been given that advice, but didnt see where you tried other high quality cables or not.

I watched your video. Doesn't look blurry to me so. You seem to be concerned about HDR not being supported at all resolutions and refresh rates you have. Me, if it works at one I like, I am fine with it.

As for your CGG9, anything at 1440 p has always looked blurry to me on that scale.

This might be a case where the M3 doesnt do what you want to do and you have to return it.
 

KRSogaard

macrumors newbie
Original poster
Jan 3, 2024
3
1
The way that scaling works on macOS is if you want a non-integer scaling factor (1.5x as opposed to 2x), the operating system's backbuffer is double the target resolution. For example, when you click the option for 3200x1600, the OS renders at 6400x3200 with 2x scaling, then scales that down to the native resolution (3840x2160 in your case) using bilinear sampling. Yes, it's bad. It also means that an HDR buffer at that 6400x3200 resolution is probably too large for the system to handle. I don't know how much memory your system has, or if that even makes a difference. You could look into alternative display handling apps such as https://github.com/waydabber/BetterDisplay and see if you get the results you're looking for. Or just accept the 1920x1080 scaled resolution.
It just seems mind-boggling to me that Apple have decided to break any monitor that is less then 4k, or 4k monitors that is bigger then 24" so i though there must be something i am missing, as everything works great on Windows and with the Intel Mac.
 
Last edited:

Bigwaff

Contributor
Sep 20, 2013
2,742
1,831
It just seems mind-boggling to me that Apple have decided to break any monitor that is less then 4k, or 4k monitors that is bigger then 24" so i though there must be something i am missing, as everything works great on Windows and with the Intel Mac.
Did you try BetterDisplay as suggested by @amasondev ? More than likely you'll find a resolution (scaled / HiDPI) which works well w/ your display... and there is a lot to be said for quality cables.
 

Two Appleseeds

macrumors member
Mar 14, 2022
46
332
Had major issues with certain cables. Sometimes it seems like a cable works for most things/other computers but they can be weird with Apple products. Had major issues with an HDMI cable that worked perfectly with everything else but not my Apple TV. Changed the cable. Issue solved. Overall, sounds like the issue is with your setup not the macbook.
 

KRSogaard

macrumors newbie
Original poster
Jan 3, 2024
3
1

Chancha

macrumors 68020
Mar 19, 2014
2,314
2,141
Screenshot 2023-12-23 at 16.50.51.jpg
I have a M3 Max 16" base and and LG CX. Using a known good HDMI2.1 cable, I got similar combination of display output limits as yours. Notice that with an LG you can press the green button the remote multiple times to get that rectangle HUD to appear that shows what input signal the TV is currently getting (from the MBP). The above 3 settings illustrate that the UI scaling needs to be at 2304x1296 (actual buffer 4608x2592) or less in order for the full settings to be available, at least on my set up with M3 Max + LG CX. (the CX's HDMI2.1 had a nerfed bandwidth cap where your C2 does not)

The above user saying the buffer size being the cause is correct. I don't believe using 3rd party utility like BetterDisplay will be able to get around this, since this is a hardware limit presumably the display buffer portion on the M3 Max SoC, it is an on-die circuity that dictates how large a frame can be.

The problem is the refresh rate and also the bit depth (being 10bit HDR) is further increasing the buffer size. So without using 3rd party hacks, you have to make compromises between the display perimeters, for instance you may have chosen a specific non-integer scaling, and want no fuzziness (thus need 10bit), in which case you have to decrease refresh to 60Hz to let those other options appear. Conversely I use my example, when I am using my MBP to game on the LG TV, I want max refresh and HDR lighting effects and 4k native output, thus I just use no scaling where the UI looks impossibly small for macOS general use but once I am in-game it is fine because the game UI is designed to be blown up at native res.

Then on your CRG9; I have no personal experience with ultra-wides, but, I vaguely remember reading on this forum when M1 Air was new, some users had the exact same problem. Again the limit is in the buffer limit, it seemed the M1 buffer could not handle horizontal pixel dimensions of higher than 10000 pixels, or something to that effect. So with the LG the limit is the total bandwidth for a certain period of time (not per frame, as decreasing to 60Hz gives you back the bandwidth). But on a 5120px ultra-wide the limit is the actual pixel width of one frame.
 
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