VRR Flashing Black screen

Talk about AMD's FreeSync and VESA AdaptiveSync, which are variable refresh rate technologies. They also eliminate stutters, and eliminate tearing. List of FreeSync Monitors.
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rootsoft
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Joined: 01 Nov 2014, 13:07

VRR Flashing Black screen

Post by rootsoft » 18 Feb 2021, 17:28

Sup guys,

I have an issue with the https://www.acer.com/ac/en/US/content/p ... redatorx34. Fairly new monitor in the market it seems, I picked it up at MicroCenter and I felt in love with the quality of this panel. I have not experience an display that has such clear image and good color before. So, that aside I have this weird issue:

phpBB [video]


It only happens when VRR is enable and only as pronounce in some games. Normal game play is fine, its mainly while browsing through menus? I have a AMD video card, I have a hunch it might be related to that? Hoping someone has seen this and maybe there is a fix.

Thank you!

Edit:

I tried changing the FreeSync Range Using CRU

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Chief Blur Buster
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Re: VRR Flashing Black screen

Post by Chief Blur Buster » 18 Feb 2021, 18:10

Try 55Hz-180Hz or 65Hz-180Hz VRR range in ToastyX CRU.

Do not forget to reboot or run ToastyX restart64.exe before launching your game.

Blur Busters recommendation nowadays is to raise min-Hz to 55Hz or 65Hz for FreeSync because it improves low-framerate quality for >180Hz+ monitors.

For 144Hz, they still need 48Hz or 52Hz or 55Hz min-Hz, but for 180Hz and up, a min-Hz of 65Hz actually improves quality anyway for multiple reasons.
- Fewer inversion artifacts
- Fewer black screens
- Less flicker during dramatic framerate changes
- LFC penalty becomes relatively insignificant when the VRR range is extremely wide (3:1 ratio or 4:1 ratio for maxhz:minhz) and LFC becomes superior to native Hz at a certain point.

If you still get black screens, try complete uninstall-reinstall of drivers.
Head of Blur Busters - BlurBusters.com | TestUFO.com | Follow @BlurBusters on Twitter

       To support Blur Busters:
       • Official List of Best Gaming Monitors
       • List of G-SYNC Monitors
       • List of FreeSync Monitors
       • List of Ultrawide Monitors

rootsoft
Posts: 35
Joined: 01 Nov 2014, 13:07

Re: VRR Flashing Black screen

Post by rootsoft » 19 Feb 2021, 02:15

Chief Blur Buster wrote:
18 Feb 2021, 18:10
Try 55Hz-180Hz or 65Hz-180Hz VRR range in ToastyX CRU.

Do not forget to reboot or run ToastyX restart64.exe before launching your game.

Blur Busters recommendation nowadays is to raise min-Hz to 55Hz or 65Hz for FreeSync because it improves low-framerate quality for >180Hz+ monitors.

For 144Hz, they still need 48Hz or 52Hz or 55Hz min-Hz, but for 180Hz and up, a min-Hz of 65Hz actually improves quality anyway for multiple reasons.
- Fewer inversion artifacts
- Fewer black screens
- Less flicker during dramatic framerate changes
- LFC penalty becomes relatively insignificant when the VRR range is extremely wide (3:1 ratio or 4:1 ratio for maxhz:minhz) and LFC becomes superior to native Hz at a certain point.

If you still get black screens, try complete uninstall-reinstall of drivers.
Hi Chief!

I tried your suggestions and I'm still experiencing the same issue.

I love this monitor and I don't have a NVIDIA video card to test with(i think its an gsync+amd driver issue)

rootsoft
Posts: 35
Joined: 01 Nov 2014, 13:07

Re: VRR Flashing Black screen

Post by rootsoft » 19 Feb 2021, 02:34

Ok! Chief!

I think I got it.

in CRU i found two places to edit the range, reset and it worked!

I had to set the range from 55-144 and its working as expected! When it was 55-180 the issue was happening.

I'm fine running this beauty at 144 at all times.

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Chief Blur Buster
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Re: VRR Flashing Black screen

Post by Chief Blur Buster » 19 Feb 2021, 05:13

rootsoft wrote:
19 Feb 2021, 02:34
Ok! Chief!

I think I got it.

in CRU i found two places to edit the range, reset and it worked!

I had to set the range from 55-144 and its working as expected! When it was 55-180 the issue was happening.

I'm fine running this beauty at 144 at all times.
Interesting! So some max-Hz issues. That's far less common than min-Hz issues. Possibly near max-Hz overclocks it a bit much.

You could edit the range from 55-175 or 55-179 and see if that helps.
Head of Blur Busters - BlurBusters.com | TestUFO.com | Follow @BlurBusters on Twitter

       To support Blur Busters:
       • Official List of Best Gaming Monitors
       • List of G-SYNC Monitors
       • List of FreeSync Monitors
       • List of Ultrawide Monitors

rootsoft
Posts: 35
Joined: 01 Nov 2014, 13:07

Re: VRR Flashing Black screen

Post by rootsoft » 19 Feb 2021, 14:14

Chief Blur Buster wrote:
19 Feb 2021, 05:13
rootsoft wrote:
19 Feb 2021, 02:34
Ok! Chief!

I think I got it.

in CRU i found two places to edit the range, reset and it worked!

I had to set the range from 55-144 and its working as expected! When it was 55-180 the issue was happening.

I'm fine running this beauty at 144 at all times.
Interesting! So some max-Hz issues. That's far less common than min-Hz issues. Possibly near max-Hz overclocks it a bit much.

You could edit the range from 55-175 or 55-179 and see if that helps.
Chief,

It seems going all the way up to 180 works now with no issues.

I guess I just had to reinstall my drivers, try CRU once and it corrected w/e issue there was?

I'm back on 55-180 range and it works perfect! Thanks!

If anyone is on the fence for a Predator X34 144hz/180hz version THIS THING IS A BEAUTY, GET IT.

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Chief Blur Buster
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Re: VRR Flashing Black screen

Post by Chief Blur Buster » 19 Feb 2021, 16:57

rootsoft wrote:
19 Feb 2021, 14:14
I guess I just had to reinstall my drivers, try CRU once and it corrected w/e issue there was?
Yes. The drivers (instead of monitor) control the timing of refresh cycles, since the monitor is synchronizing to the software.

<Technical>
Frame presentation APIs such as Present() instantly triggers refresh cycles during VRR. That allows framerate and Hz to be in perfect sync to each other -- and eliminate framdrop-style stutters -- and de-stuttering smooth framerate changes -- but creates problem when framerates exits the VRR range (frametimes longer than min-Hz, for example).

Software bugs with VRR can cause blackouts on many FreeSync monitors, since it is kind of a real-time operation for software, and drivers that violate VRR ranges is sometimes more common than it should be.

Native G-SYNC chipped monitors will often be able to refresh unattended if drivers don't begin sending a new refresh cycles, but FreeSync doesn't do this -- the graphics driver is responsible for beginning to transmit a new refresh cycle on time. But oftentimes, software is not microsecond precise.

Ideally, manufacturers need at least fraction of a Hz of safety headroom below min Hz, to allow software imprecisions. For example, panels should support ~35-240Hz for a software-based 48Hz-240Hz VRR range. Unfortunately not enough manufacturers include enough min-Hz VRR headroom, and sometimes.... software-driven refresh cycle imprecision occurs.

Drivers (including Microsoft non-realtime behaviors) accidentally keeping the monitor unrefreshed too long -- is a major cause of FreeSync monitors going blank below min Hz.

VRR blackout issues are usually caused by software tolerance issues. A well-tuned Windows system may have no problems, while a flawed driver installation (on a monitor without min-Hz tolerance) may fail to keep up the refresh cycles.

Besides this, behaviours such as flicker (refresh-cycle decay, inversion algorithms, etc), also make it favourable to raise the min-Hz, to force the drivers to refresh more frequently.

LFC is simply driver-initiated automatic repeat-refreshes, but it must be done before monitor refresh cycles times out (and goes blank automatically). Even if sometimes minor stutters occur from new-refreshes colliding with monitor-busy-repeat-refreshing events. (But at 180Hz, a monitor is only busy for 1/180sec executing a repeat-refresh. And since it's chance whether a new frame may occur beyond halftime or before halftime of that refresh cycle -- so halve that. 0.5/180sec = 1/360sec average stutter caused by an LFC miss. 1/360sec stutters are very hard to see at 30fps or 40fps anyway, so a higher min-Hz is perfectly fine for wide-VRR ranges (3:1 ratio or bigger). So you're trading away those annoying blackouts for potentially un-seeable added stutter at low frame rates.

This was a bigger problem with 144Hz FreeSync monitors, where a 0.5/144sec (3.5ms) stutter may become visible during 55fps operation (18ms), since 3.5ms:18ms is an approximately 20% stutter (e.g. a frame step between adjacent frames suddenly increases by 20% in movement distance).

But as VRR ranges get wider, 240Hz, your 55fps material (21ms) versus the halftime of 240Hz repeat-refreshes (2ms) means stutter deviations are smaller -- less than a 10% stutter. This starts to become impossible to see for most people, and still looks like perfect 55Hz VSYNC ON with the stutter deviation so small that the low-framerate stutter becomes hidden in the plain display motion blur of the lowness of frame rate (as you've noticed, the lower the frame rate on VRR, the more motion blur, until it falls into the stutter-visibility region of the stutter-to-blur continuum).

TL;DR: LFC has far less penalty when VRR range is extremely wide, and LFC (hidden repeat refreshes) can be superior in image quality to extremely low native refresh rate because of various reasons. You you get the advantages of a higher min Hz (less flicker, less GtG decay, more consistent color equalling colors of max-Hz, avoid varying-ghosting effects, fewer inversion-artifacts such as scrolling chessboard effects, etc). Since picture quality at different refresh rates may be slightly different.

When LFC is absent of refresh-cycle collision events, it looks indistinguishable to well-done low-Hz (since repeat-refreshes ideally behave like no-operations, as long as they don't delay the new frame). At some point, the higher-min-Hz pros starts to exceed the LFC-cons when "busy-doing-refresh-cycle" events are very brief (1/240sec or faster).

So that's why Blur Busters now feels higher min-Hz on wide-VRR-ranges produces superior VRR experiences, visually -- not just for blackout reasons.

It is /sometimes/ ALSO the manufacturer's fault, occasionally
That said, manufacturers should include lower undocumented min Hz in more FreeSync panels just as safety headroom (even as low as 30-40Hz). This safety headroom is just accommodation for software performance -- graphics drivers too slow to refresh frequently enough risks these blackouts you saw. There should always be more undocumented min-Hz headroom below the EDID-advertised VRR range, but unfortunately many panels cheap out and have no safety margin -- creating lots of blackout complaints.
</Technical>
Head of Blur Busters - BlurBusters.com | TestUFO.com | Follow @BlurBusters on Twitter

       To support Blur Busters:
       • Official List of Best Gaming Monitors
       • List of G-SYNC Monitors
       • List of FreeSync Monitors
       • List of Ultrawide Monitors

rootsoft
Posts: 35
Joined: 01 Nov 2014, 13:07

Re: VRR Flashing Black screen

Post by rootsoft » 19 Feb 2021, 17:58

Thank you so much for the help and the explanation.

You are amazing.

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