[Weissrolf]

Concerning the brightness drop in HDR mode, I measured power at the wall: 100% brightness showing fullscreen white drops from 172 W to 93 W in less than 30 seconds. 96% brightness stays at 167 W without dropping.

When the monitor changes from HDR to User mode by sending brightness commands via DDC/CI then it drops to 75 W and gets considerably darker.

At the same time 75 W in real SDR mode manages to reach close to the brightness of 167 W in HDR mode (hard to discern by eyes, needs measuring) and consequently is a *lot* brighter than 75 W in HDR mode.

[PCM2]

There were definitely no significant drops in brightness by 30 seconds on my unit, it comfortably maintained >1000 nits as its sustained full screen brightness. Doesn’t seem to be happening on Rakni’s unit either. If this persists on your new unit as well, I wonder if this is an overheat protection mechanism. Maybe that was somehow disabled on my test sample or I kept the room cool enough to avoid it triggering. What temperature is the room you’re testing this in?

[Weissrolf]

Currently about 25°C. The central upper exhaust grill (probe stuck inside) measures less than 38°C at 100% SDR 255 brightness and less towards the edges. Switching to HDR with brightness 97-100 drops brightness and power usage immediately while at 96 it does not drop at all even after several minutes.

On a side-note: local dimming is useful for dropping power usage (and thus heat) at 96% from 167 W to 125 W using “fast” and 119 W using “moderate” and “low” while showing fullscreen SDR 255 white (Windows SDR slider at 100). Unfortunately the dark bias also dims SDR 255 white visibly, so there are trade-offs. Fullscreen HDR white is not affected, of course (aka full 167 W).

[Weissrolf]

It just occurred to me: SDR mode only using 75 W at 100% SDR brightness means that the backlight *is* permanently dimmed at a fixed level in SDR mode even with “Max Brightness” being enabled.

[PCM2]

SDR is not supposed to go as bright as HDR so it’s not surprising power consumption would be significantly lower. It’s not unusual for monitors to reserve their highest brightness levels for HDR and that was certainly the case with the X32 FP.

[sblantipodi]

Sdr goes up to 550 nits, HDR up to 1200 nits more or less…

[Weissrolf]

There is still a difference, though. In SDR mode the backlight is dimmed at 100% SDR brightness, using less power. In HDR mode the backlight runs at full power when displaying fullscreen SDR white and then “dimms” SDR white via liquid crystal orientation (aka blocking the light). So fullscreen SDR white in SDR mode uses less backlight than the very same fullscreen SDR white in HDR mode.

Personally I don’t see the benefit of limiting SDR mode brightness to be lower than HDR. If the monitor can achieve it then let the users choose how much backlight/brightness they want to use. Seems more like a “don’t confuse the user” decision on Acer’s part.

[PCM2]

The Windows desktop and other SDR content isn’t designed to be viewed under HDR, it is always unbalanced one way or the other including colour inaccuracies, gamma imbalances and in many cases appearing ‘flooded’ due to digital brightness adjustment (which applies to the X32 FP). Plus OSD controls are typically restricted. The fact white luminance levels are restricted despite the backlight acting as it would under HDR when displaying much higher brightness levels certainly isn’t an issue specific to this monitor.

[Weissrolf]

No, not specific to the monitor. Someone somewhere decided that peak HDR luminance always had to be higher than peak SDR luminance even in SDR mode, which then limits SDR luminance below what the monitor would be capable of. Fortunately 350-400 cd/m² usually is enough for daylight rooms, even though the dark biased local dimming can make that more problematic when used with SDR content.

[Rakni]

Hi all,

sorry for the late reply, but today i connected my PS5 to the X32 and tried messing with the settings like Weissrolf described. Here are my results:

https://imgur.com/a/fVW48Ro

Nothing changes if I turn on/off DDC/CI. The monitor remains in HDR mode. I even restarted the PS5 with DDC/CI off but nothing changed. I added two pictures of FFXVI where you can’t see sh*t in HDR but everything becomes much brighter in SDR.

At last i tried adjusting the brightness and something felt off. The first two pictures where you set the maximum brightness showed the sun symbol and could be adjusted until the symbol disappeared. The third picture where you set the minimum luminance showed nothing. It is always a black square on all settings.

Hope this helped a little. If someone wants me to test something else just ask. I put my PS5 back in the living room tonight =)

[PCM2]

Thanks Rakni, don’t worry about the delayed reply. You seem to have confirmed that disabling DDC/CI doesn’t alleviate the very clearly dark HDR on the PS5. Which is unfortunate, but it’s good to have it tested as you have and have provided some useful images for those without a PS5 illustrating the issue.

[Rakni]

No problem PCM2,

thank you for your cool reviews! Happy to help.

[Weissrolf]

Too bad with the PS5, but it was worth a try. Thanks for sharing.

My second X32 unit arrives a few days ago. Here are some comparisons of the second unit (B) to my first unit (A).

The Good (unit B vs. A):

– Considerably better – but still somewhat mediocre – backlight bleed on B, which also leads to better native contrast in those edge areas.
– Considerably less vertical “scanlines” on B, to the point of hard to even reproduce. I also noticed that A mostly produces “scanlines” in its horizontal center (third) only, but not towards the edges. Since this is especially problematic in HDR mode and seems to vary in strength I suspect that heat plays a role, too.
– The display on B can be moved up (1 cm) and down (2 mm) further on its stand. The stand of A seems to block too soon at its upper boundary as there is still some visibly free space on the guiding rails.
– Both units are audibly dead silent in all modes (SDR and HDR)!

The Bad (one or both units):

– B suffers from uneven white-point distribution over its screen area. It’s more greenish to the left and more purplish to the right. It’s subtle, but especially unpleasant (and noticeable) with brighter backgrounds (like white websites).
– Both units struggle with waking up from prolonged sleep when Windows enters display power-saving mode (not PC standby, just display). They hand, don’t react to button presses and need some fiddling with keeping the power button pressed or unplugging the power cord to get back a picture.
– The Acer Display Widget does not allow to control Brightness in HDR mode using firmware .09, .10 or .15, while the OSD does allow that with .15 at least. Controlling brightness via third party DDC/CI application throws both units out of HDR mode into a much darker User mode with .15, but doesn’t do anything in HDR mode with .09 and .10.
– Maximum brightness in SDR mode struggles to overpower my daylight room when I open the shades between morning and middle of the day. It gets better in the afternoon. Knowing that the monitor is capable of higher brightness and only artificially limited to lower SDR maximum is an unnecessary let-down.
– Dynamic Overdrive or having an OD setting between “Off” and “Normal” would be a welcome addition for using VRR at varying refresh-rates. “Normal” is often too strong below 160 Hz and Normal too weak above 120 Hz.
– Local Dimming cannot be set to one of the quick access buttons.

The Ugly (both units!):

– VRR + DSC connected via Displayport 1.4a to my 2070 Super still produces massive (!) dropouts on both units, especially in the 115-125 Hz range. I tried firmwares .09, .10 and .15, same results.
– Using Brightness 97-100 in HDR mode leads to considerable drop in brightness (and corresponding power usage at the wall) within 30 seconds on both units. Using Brightness 96 or less fixes this (and 96 is brighter than 97-100 then). No such problem in SDR mode.
– The tiny case frame around the side and upper display edges are slightly bend outwards, leaving gaps between frame and panel. This leads to backlight escaping through these gaps between panel and frame at the upper edges left and right and 8 discrete points along the upper edge of the panel/frame (single square holes towards the sides, double holes for the two center ones).

Bonus observations (both units):

– Local Dimming only ever completely disables LEDs for full black in SDR mode using Brightness up to 20 (fullscreen black, may vary slightly with mixed content). It changes in discrete steps every 19-20 Brightness levels. In HDR mode the backlight is never turned off for full black in any zone at any Brightness setting. Minimum HDR black seems to corresponds more to SDR step 3 (40-58) than step 2 (21-39). I speculate that this is to keep blooming and black crush in check.
– Firmware .09 already allowed to change Overdrive modes in combination with VRR, but only via Acer Display Widget, not via OSD. Firmware .10 removed that from both OSD and Acer Display Widget and only .15 re-introduced it to both.
– Firmware .15 also changed the brightness range when “Maximum Brightness” (MB) is disabled. Before it started at lower brightness (similar to MB enabled) but peaked lower at 100. Now Brightness 61 is the same as 100 was before and anything above uses local dimming black step 2 (same as 21-39 with MB enabled), but in return Brightness 0 is considerably brighter with MB disabled vs. enabled (and vs. older firmware).

[PCM2]

Thanks for sharing your extensive thoughts and findings with both of your X32 FP units. Some interesting inconsistencies between the units there – it’s a shame they both seem allergic in some ways to your 2070 Super. I assume you’ve also tried a better quality DP cable than the ones that come with the screen? Just in case that alleviates some of the issues (may not, but worth trying).

[Weissrolf]

Tried different cables and ports, which all worked without dropouts connected to the Asus PG32uqxR.

Why I wrote about a possible temperature issue with vertical “scanlines” is, because I can make those lines appear on the second unit by running it in HDR mode for some time. I think heating it up makes the problem become more obvious. Running at 0% SDR brightness also seems to bring them out very subtly (best tested with solid white/bright gray and moving the head/eyes). Overall it’s a more minor nuisance on the second unit while it was rather obvious in the center third (horizontal) of the first unit.

[Rakni]

Hi Weissrolf,

like PCM2 said, I also think the 2070 Super might be the culprit. I tried to replicate the HDR brightness drop with brightness 97 and above but I really can’t recreate it. The drop outs never happened to me in any game but i I had them in the game menu of World War Z.

My Monitor goes to sleep after 10 Minutes but it never had problems with waking up.

With all your testing and observations, I miss your conclusion. What have you learned by comparing all those monitors?

[Weissrolf]

I looked further into the Brightness 97-100 issue. It only happens when local dimming is disabled, but also happens connected to the Intel iGPU via HDMI then.

Unfortunately the joystick on the second unit is already giving up and has a hard time accepting clicks to the right.

No conclusion yet, just observations. The first X32 unit is going back tomorrow, though.

[Rakni]

I can confirm your observation. With local dimming disabled my monitor will get dark from brightness range 97-100. It will get much brighter if i change back to 96.
Only if HDR is enabled and local dimming is disabled.

[PCM2]

Interesting, though basically a combination nobody would use in practice.

[Weissrolf]

Likely, yes.

The standby issue is a bit of a nuisance. The monitor basically freezes and becomes unresponsive to button presses other than the power-button. And even that one just changes the LED from orange to blue for some seconds and then either turns it off or changes back to orange. Unplugging the Displayport cable has no impact, nor does restarting the PC.

Windows still recognizes the monitor and works properly – as verified via second monitor – it’s the X32 itself that freezes. You cannot even select an input then. I once got it to wake up again via erratic button pressing, but usually you need to pull the power-plug to make it work again.

[Author]

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