Some thoughts on Acer X32 FP (local dimming and screen surface)

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      Thanks for sharing those measurements! The X32 FP looks to offer decent clamping of the colour spaces so a useful option for some, even though the gamma tracking is a bit ‘high’.


        Indeed, it is strange that in the box a calibration report is included for the sRGB color gamut, while the Standard mode delivers a better color accuracy and gamma tracking than the factory calibrated sRGB mode.

        Another remarkable thing I saw is when in HDR mode and local dimming is enabled (either Low, Average or High) then the saturation of green is lower. Disabling local dimming while still in HDR makes green saturated again.


          AUO panel in Asus PG32UQX had something similar to A-TW polarizer according to TFTCentral:

          So it’s possible that was carried over to newer panel.

          Not sure if I’ve yet seen anything about same with CM Tempest GP27U.


            ‘Local Dimming’ often involves localised and scene-dependent gamma changes. Is that something you observe in HDR only and is it all greens or just in certain scenes (dependent on background shade)? Some greens should actually be toned down from their heavily oversaturated ‘SDR’ (non-colour managed for sRGB content) state if being shown correctly under HDR, so it’s possible they just calibrated HDR appropriately with ‘Local Dimming’ in mind and not without.


              Indeed, when I first saw the limited glow of the X32FP it reminded me exactly to what TFT central wrote about the screen you mentioned. This also helps reduce halo’s seen from an angle.


                It was green only, on the desktop, but I’m not able to reproduce it anymore. Maybe it had something to do with the Saturation sliders in OSD, because I’d set them a little higher. Maybe they were reacting different with local dimming disabled. I could try that again later.

                I also checked the NFR option and it is correct what you were saying: with FreeSync enabled and the refreshrate set to 160Hz for example, while in the ingame framerate is set to 80 I saw the NFR showing 160. Still certain blur was visible. But when I changed the framerate to 160, there was almost no ghosting anymore, it was butter smooth (it was staying the whole time on 160). Such a high framerate was only possible in Forza 4 with the settings set to max. Forza 5 is clearly to heavy maxed out for my 3080 Ti.


                  Regarding the change in saturation of green, it happens only via HDMI, not DisplayPort. So when enabling local dimming and connected with HDMI the green changes.

                  Another nice thing to mention is that Acer is trying to solve the flickering caused by the too aggressive local dimming setting Fast.


                    Sounds like an odd firmware bug or quirk to me. On some models I notice some odd quirks under HDR that only apply when using HDMI or DP – and sometimes depending on whether using an AMD or Nvidia GPU, even. Did you contact Acer and receive confirmation they’re working to address the X32 FP‘s flickering with the ‘Fast’ local dimming setting, or was this confirmed via Reddit?


                      I’m in contact with Acer support, I’ve made some movies of the flickering and provided these to them. The flickering occurs both on HDMI and DisplayPort with and without VRR enabled. It looks like the problem is a combination of too fast transition time and gamma changes.

                      The flickering is clearly visible in the following video I’ve made of The Shadow of the Tomb Raider. You can also see that the problem does not persist when I switch to the setting Low: video


                        Ah yes it’s very clear in that video – good demonstration and glad Acer are aware of and hopefully able to tweak this. πŸ™‚


                          That bad flickering just proves that those doing decision are either blind, or shouldn’t qualify for handling any ship, including citizenship.
                          (they’ve had already over half year to tweak firmware…)

                          So any more expriencing with overdrive at different frame rates?
                          Also with that mention of rather grainy coating have you tested at what kind viewing distance it shows?

                          Have seen few more decent prices for this now.


                            No, new experiences with overdrive, it looks like it is best to have VRR enabled and having a fast graphics card.

                            Regarding the coating, it is less visible when your eyes are looking straight at the screen (90 degrees), so in the middle of the screen, but it is quite obvious at the sides then. That means when you’re increasing the distance the viewing angles become smaller and mitigates the problem.

                            I’m living in the Netherlands, so my apologizes for not perfect English πŸ™‚


                              Capping framerate lower in driver settings would be way to test overdrive tuning at lower refresh rate.
                              But for actual gaming VRR is of course really the only way.
                              And when overdrive is setting locked with it, locked setting should be good also to closer to 60Hz level.

                              I have 30″ 16:10 which is actually some millimeters higher in height than 32″ 16:9 and use about 60cm – 70cm viewing distance.


                                You should be able to get a gauge for overshoot levels if you switch the monitor over to 60Hz with VRR enabled. The pixel response behaviour doesn’t typically vary hugely at a static 60Hz refresh rate vs. a similar refresh rate naturally achieved during VRR. So you could perhaps observe Test UFO at 60Hz (‘G-SYNC Compatible’ active) and see how it looks. πŸ™‚


                                  I’ll try that later.

                                  Something else, did you notice on some HDR monitors that the color temperature is changing between darker and lighter parts when local dimming is enabled? On the Acer X32 FP when image is dark the color temperature will raise from 6500K to around the 8000K or more. It is also clearly visible when disabling local dimming while in a dark part of a game for instance:


                                  comparison 2


                                    Interesting. From the images it appears that the monitor has a cool cast and high white point with ‘Adaptive Dimming’ on (left side), but with ‘Adaptive Dimming’ off (right side) it looks far too warm in comparison. I appreciate the camera will be compensating in various ways plus capturing high red energy from the QD LED backlight, which can throw off the representation. It’s not unusual to have different calibration with local dimming active and deactivated and there can also be some localised differences with local dimming active. So depending on how much light shade is being displayed. The monitor may be able to achieve higher brightness when it targets a cooler white point, so that could explain this behaviour. It’s also why I don’t like it when reviewers give a single white point reading for HDR – it is too dependent on the content, so this is something where general impressions and assessment can be more helpful. Did you specifically measure this and were able to ascertain it’s close to 6500K with the setting disabled and closer to 8000K with it enabled? And does this change if a larger section of the screen is displaying white?


                                      There’s definitely A-TW polarizer or what ever AUO calls it.
                                      There’s no normal IPS-glow:
                                      Which shows as bright corners:
                                      ​And coating is some semi-glossy:

                                      Though with review done over three months ago firmware was old and overdrive definitely last summer bad.

                                      Degrader also has another good Fast mode local dimming flickering video:


                                        Here is a comparison between FALD on and off, the difference is around the 1500K: Color temperature FALD on and off


                                          Yeah, I think it is as good as having an A-TW polarizer, but the strange thing is is that AUO never mentioned this advantage in their marketing material: AmLED. I really like the panel about this. Today Tweakers, a Dutch IT site, published their review of the GP27U and the reviewer mentioned that it suffers from ips glow even with FALD on. So the X32 FP is definitely better in this regard.

                                          I hope to hear from Acer back this week if they were able to replicate the flickering issue.


                                            Good to see definite confirmation that it’s a ‘low glow’ (or perhaps ‘very low glow’) panel – indeed those benefits persists even with FALD enabled as the zones are still much larger than pixels and are rarely just displaying pure black. Because it’s viewing angle dependent, it can be quite noticeable towards the corners of the screen. Perhaps it wasn’t specifically marketed for the AmLED panels because it doesn’t apply to them universally? The GP27U technically uses the M270QAN07.0 CELL with a custom backlight fitted, so it doesn’t necessarily benefit from all of the features of a pure AmLED panel (advertised or otherwise).

                                            The very light matte screen surface is nice to see. Yes, it’s a shame about the graininess to the surface texture – but it still helps with the vibrancy and clarity potential. And minimises the amount of diffused glare from the room which could upset the image, too. It’s certainly possible the higher white point target is to help maximise brightness potential with local dimming active. It’s not unusual to see that sort of deviation with this in mind – and it isn’t an extreme target like ~10,000K so hopefully isn’t something you find uncomfortable or extremely cool-tinted. Particularly when using that mode on the X32 FP in isolation (i.e. not comparing to another screen or setting with warmer white point). πŸ™‚

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