Variable Refresh Rate (FreeSync / GSync) Flicker

[DianaofThemiscyra]

Support for Variable Refresh Rate has been introduced on Monterey. macOS did not support it before. If you set your screen to a fixed refresh rate, the flicker should disappear.

The only way for me to solve this flickering problem was changing the monitor resolution from 1920 x 1080 60hz to 1680 x 1050 60hz. Before Monterey this flickering didn't happen. I also sometimes use the same monitor with a windows 10 computer from my husband at the maximum resolution 1920 x 1080 60 hz and never had any problem. So yes, this is an issue of Monterrey and not on my monitor (which by the way HAS NOT VRR).

 

[Fravin]

So yes, this is an issue of Monterrey and not on my monitor (which by the way HAS NOT VRR).

Sure thing. It’s absolutely a software issue. I think Apple is messing with RGB signal trying to decipher if the display connected is a TV or a monitor.

 

[kindof665]

Still no fix in macOS 12.1 RC1. Ridiculous...

Hey there is the issue fixed by now for you ? i have recently got a mac studio 3 days ago and am facing the same issues!

 

[CMMChris]

No, currently running 12.4 Developer Beta 2 and it is not fixed. I guess they won't fix it in Monterey. Maybe in macOS 13 - but my hopes aren't high. Submit a bug report to Apple and mention my feedback ID for linking (FB9722940).

 

[pgharavi]

I can't even get VRR as an option on my LG C1 despite it supporting Freesync, GSync, and standard VRR. I have the M1 2021 16" MBP.

Anyone know why?

 

[CMMChris]

Well, ask crApple.

 

[phrehdd]

I wish your poll included non G-Synch and FreeSynch..as in regular monitors who too have this problem. That is the case of my monitor BenQ PD2700u.

 

[CMMChris]

That's a different issue, there are other topics for that. This topic is strictly for Apple's flawed VRR implementation.

 

[phrehdd]

That's a different issue, there are other topics for that. This topic is strictly for Apple's flawed VRR implementation.

Seems that if the symptoms are somewhat the same, they may be related in how Apple handles some types of monitors or defaults to what is not usable.

 

[joevt]

I did some VRR testing with my Mac mini 2018 with W5700 eGPU and Acer XV273K (FreeSync 48-144Hz for 1080p, 1440p, 1908p). I made some notes at:
https://forums.macrumors.com/threads/mac-mini-4k-120hz.2267035/post-31052119
I haven't noticed any flickering so far.

 

[CMMChris]

Seems that if the symptoms are somewhat the same, they may be related in how Apple handles some types of monitors or defaults to what is not usable.

It is not the same. M1 Macs have been plagued with flickering on some displays in Big Sur even before support for variable refresh rate screens has been introduced in Monterey. There is some other bug that can cause flicker with some monitors and it is not related to VRR.

The issue discussed here IS related to VRR because flicker can be fixed when disabling VRR in either macOS display settings or the monitor itself.

I haven't noticed any flickering so far.

Well, it does work properly with some monitors, so you are lucky enough to own one that plays nicely with macOS's VRR implementation. Unfortunately, that's not the case for all monitors. My Samsung screen still does flicker heavily when enabling VRR. My HP Gaming 32 does not flicker with enabled VRR but VRR does not work properly, which is visible by stutters and error spamming in Console (Invalid actual_host_time received from display / defaulting to 60Hz).

Both screens work flawlessly with enabled VRR in Windows or on my Xbox Series X.

 

[phrehdd]

It is not the same. M1 Macs have been plagued with flickering on some displays in Big Sur even before support for variable refresh rate screens has been introduced in Monterey. There is some other bug that can cause flicker with some monitors and it is not related to VRR.

The issue discussed here IS related to VRR because flicker can be fixed when disabling VRR in either macOS display settings or the monitor itself.



Well, it does work properly with some monitors, so you are lucky enough to own one that plays nicely with macOS's VRR implementation. Unfortunately, that's not the case for all monitors. My Samsung screen still does flicker heavily when enabling VRR. My HP Gaming 32 does not flicker with enabled VRR but VRR does not work properly, which is visible by stutters and error spamming in Console (Invalid actual_host_time received from display / defaulting to 60Hz).

Both screens work flawlessly with enabled VRR in Windows or on my Xbox Series X.

It remains unclear to me that what you advanced is fully correct. M1/Monterey is not dealing with signals from monitors correctly in some instances. Since FreeSynch and GSynch are sufficiently different, what remains the same is the inability to properly handshake and maintain proper screen hrtz and in some instances, resolution. This has gone across numerous monitors and what you express are a subset possibly. Some monitors other than Freesynch and GSynch monitors have responded to certain changes while others have not. M1/Monterey to many types of monitors exhibit issues. We can agree this is not the monitors at fault. Hope I am being clear here.

Years ago, there was an issue with certain output from Macs (especially TVs) that would not hold proper resolution nor hrtz correctly. The end result were a couple of options - A software that forced resolution and hrtz and the other was an intermediate device that fed a constant EDID value back to the Mac in question. The issue occurred with both LCD and plasma TVs. It is obvious that both technologies are vastly different yet the issue remained the same for both. Even within LCD systems the guts may be sufficiently different (Samsung vs Toshiba) etc.

 

[jdb8167]

I can't even get VRR as an option on my LG C1 despite it supporting Freesync, GSync, and standard VRR. I have the M1 2021 16" MBP.

Anyone know why?

I just figured out why my 24" LG24UD58-B wasn't showing VRR on my M1 MacBook Air. Even though I was using Display Port from my Caldigit SOHO dock to the monitor it wasn't showing FreeSync as active. I just switched to directly using USB-C to DP and now I can see FreeSync and 40-60 Hz variable refresh rate. It doesn't flicker.

Even though it works and doesn't flicker, I'm not sure what use a variable rate between 40 and 60 Hz is though. Can someone explain the usefulness of such a small variable refresh range? I'm not really a gamer so even if it does smooth out some frames on a game, I would never notice that. Is there anything else that it is good for?

 

[CMMChris]

Play a game that only reaches 40 to 50fps with VRR and without at 60Hz fixed. You will notice quite a big difference. With fixed 60Hz the lower framerate will be much more visible.

 

[jdb8167]

Play a game that only reaches 40 to 50fps with VRR and without at 60Hz fixed. You will notice quite a big difference. With fixed 60Hz the lower framerate will be much more visible.

That makes sense. And on my M1 MBA, it is likely that even a pretty well optimized game would be only 40-50 fps. Is it doing anything useful when running not in a game in the system? Scrolling in Safari for example?

 

[CMMChris]

Unlikely, there should be very few cases where scrolling dips below 60fps.

 

[jdb8167]

Unlikely, there should be very few cases where scrolling dips below 60fps.

Thanks. So I guess I don't care that the Caldigit dock isn't working with VRR then. If I did run a game it is easy enough to switch to using the USB-C to DP cable instead of the dock.

 

[joevt]

I just figured out why my 24" LG24UD58-B wasn't showing VRR on my M1 MacBook Air. Even though I was using Display Port from my Caldigit SOHO dock to the monitor it wasn't showing FreeSync as active. I just switched to directly using USB-C to DP and now I can see FreeSync and 40-60 Hz variable refresh rate. It doesn't flicker.

I don't think VRR works with any DisplayPort MST hub (at least for macOS). I tried a CalDigit SOHO, a Delock 87737, and a HP Thunderbolt Dock G2.

While VRR doesn't work from the MST hub DisplayPort ports of the HP Thunderbolt Dock G2, it does work from the downstream Thunderbolt port of the dock.

These were all tested with a Radeon Pro W5700. The Intel iGPU (UHD Graphics 630) does not support VRR. For the HP dock, a GC-ALPINE RIDGE in my MacPro3,1 is used to convert DisplayPort from the W5700 to Thunderbolt.

Club-3d says their MST hubs support FreeSync, G-Sync, and VRR but I don't know if that's true for macOS. Maybe macOS doesn't support VRR from an MST hub.
https://www.club-3d.com/en/detail/2...sport_(mst)hub_displayport1.4_triple_monitor/

All these MST hubs use chips from Synaptics so I assume if one can have support for FreeSync, G-Sync, and VRR, then they all can.

Then I tried Windows 10 from a PC using a Radeon RX 580. I used GPU-Z fullscreen renderer to make sure VRR is working (the XV273K has a frame rate overlay that rapidly changes when FreeSync is working). Using any of the MST hubs locks the frame rate at 144Hz. The Radeon Software shows AMD FreeSync "Not Supported" when the Delock MST hub is used. I also tested the CalDigit SOHO (using a GC-TITAN RIDGE since the RX 580 doesn't have a USB-C port). I couldn't seem to get an image from the HP dock while in Windows... I did not try Nvidia cards (I have a Titan X and a GTX 1070).

Also in Windows, FreeSync worked from the GC-ALPINE RIDGE even though GC-ALPINE RIDGE is limited to DisplayPort 1.2 HBR2 link rate. In this case, the FreeSync Range is 48-60Hz instead of 48-144Hz (but the display shows numbers like 90Hz when doing the GPU-Z renderer test).

 

[joevt]

I couldn't seem to get an image from the HP dock while in Windows...

I restarted after updating some Windows drivers, now the dock works again, but no FreeSync from the MST hub ports, only the downstream Thunderbolt port, just like macOS. Radeon Software says FreeSync will do 48-120Hz at 4K with HBR3 link rate. Actually, the GPU-Z renderer is locked at 60Hz with 4K... so maybe macOS is more correct.

 

[pgharavi]

I can't even get VRR as an option on my LG C1 despite it supporting Freesync, GSync, and standard VRR. I have the M1 2021 16" MBP.

Anyone know why?

I just figured out why my 24" LG24UD58-B wasn't showing VRR on my M1 MacBook Air. Even though I was using Display Port from my Caldigit SOHO dock to the monitor it wasn't showing FreeSync as active. I just switched to directly using USB-C to DP and now I can see FreeSync and 40-60 Hz variable refresh rate. It doesn't flicker.

Interesting. I've tried with a high speed HDMI cable. I also tried with a USB-C to HDMI cable. In both cases, VRR doesn't show up in the system Display menu for my tv (the LG C1).

 

[joevt]

I've tried with a high speed HDMI cable. I also tried with a USB-C to HDMI cable. In both cases, VRR doesn't show up in the system Display menu for my tv (the LG C1).

The apple support document https://support.apple.com/en-ca/HT212232 says not to use HDMI. I don't know if you can get around that using a DisplayPort to HDMI adapter (the one you tried failed but maybe a different one can succeed).
I suppose with HDMI, you would have a better chance seeing a VRR mode if you used a 1080p resolution (not scaled, not HiDPI) because you're limited to HDMI 2.0 bandwidth (since Apple doesn't support HDMI 2.1 adapters very well).

 

[joevt]

My Acer XV273K only supports VRR from DisplayPort. The FreeSync option is disabled for HDMI inputs. None of the DisplayPort to HDMI adapters I tried will support VRR with my display.
Previously, I tested the adapters for HDR support. #21

 

[pgharavi]

The apple support document https://support.apple.com/en-ca/HT212232 says not to use HDMI. I don't know if you can get around that using a DisplayPort to HDMI adapter (the one you tried failed but maybe a different one can succeed).
I suppose with HDMI, you would have a better chance seeing a VRR mode if you used a 1080p resolution (not scaled, not HiDPI) because you're limited to HDMI 2.0 bandwidth (since Apple doesn't support HDMI 2.1 adapters very well).

My Acer XV273K only supports VRR from DisplayPort. The FreeSync option is disabled for HDMI inputs. None of the DisplayPort to HDMI adapters I tried will support VRR with my display.
Previously, I tested the adapters for HDR support. #21

Thanks for that link. Based on the language contained therein...

"For best performance, connect your Adaptive Sync display to the Thunderbolt port of your Mac using a Thunderbolt, USB-C, or other DisplayPort-enabled cable. Do not use an HDMI cable or adapter."

...it looks like most (all?) TVs are out of luck, as I can't think it common to have anything but HDMI on modern sets. So that would also explain why my USB-C to HDMI cable also did not work.

 

[phrehdd]

Thanks for that link. Based on the language contained therein...

"For best performance, connect your Adaptive Sync display to the Thunderbolt port of your Mac using a Thunderbolt, USB-C, or other DisplayPort-enabled cable. Do not use an HDMI cable or adapter."

...it looks like most (all?) TVs are out of luck, as I can't think it common to have anything but HDMI on modern sets. So that would also explain why my USB-C to HDMI cable also did not work.

I am sort of in the mix. My monitor is not adaptive synch but keeps now getting bounced to "40-60 hrtz" on it own though it is supposed to be a 60 hrtz monitor. My cable is exactly that recommendation to display port. USB-C to DP from a reputable cable source.

 

[Finerdly]

Fixed refresh rate still "getting lost" / being reset back to "Variable" after display sleep in macOS 12.4 - very frustrating