[PCM2]

I’m not sure about the X32Q FS (which may well have been discontinued in most markets), but an important distinction has to be made about the backlight dimming behaviour of the EX321UX. It uses what would more precisely be termed low amplitude high frequency oscillation, not ‘traditional’ PWM. The amplitude of the brightness change is much greater on ‘traditional’ PWM than what is observed on the BenQ, whilst the 4kHz cycling frequency is also far beyond usual for PWM. So for most users it will be unproblematic, even if they usually find PWM bothersome and it’s why the monitor can be marketed by BenQ as ‘flicker-free’. Nonetheless, if you know you’re extremely flicker-sensitive I appreciate it could still be an issue.

[tobias02]

Thanks for your response PCM, and yes, it’s inaccurate to call it PWM, but this oscillation is still pretty much equally bad thing.
Moreover with the EX321UX, Rtings confirmed that there is ~200Hz “pulsing” nested within ~4KHz oscillation, and that could trigger a wider audience.

But there is something more important: local dimming.
While it is likely that all MiniLED monitors use PWM and/or oscillate with local dimming, some use pure DC when local dimming is disabled.
– BenQ EX321UX and Philips 32M2N6800M both apparently oscillate with and without local dimming, while some other monitors only oscillate with local dimming enabled:
– Acer X32Q FS uses the same BOE ME315QUM-NM1 panel as BenQ and Philips, so I’d expect same behavior.
– Acer X32FP however with AUO M320QAN02.8 panel is confirmed to have no flicker when local dimming is disabled. Still that doesn’t prove it uses no DC when local dimming is enabled.
– ASUS PG32UQXR uses the same panel as X32FP, and one post mentions it flickers with local dimming
– Samsung Neo G8 at ~1KHz below RGB170 + I see it in mine too
– KTC M27P20 with AUO M270QAN07.0 panel quite clearly pulsing at ~160Hz + oscillating at ~2KHz
– Innocn 32M2V with (likely) AUO M320QAN02.6 panel at 30KHz its even officially written on the box
– AOC PD32M with the same panel as InnoCN https://www.youtube.com/watch?v=9TUEogjsEp8&t=214s + https://www.reddit.com/r/Monitors/comments/1cx16if/review_of_innocn_27m2v_innocn_32m2v_ktc_m32p10/ though they don’t say if it also flickers with local dimming disabled.

There are only two monitors that look like not using PWM/oscillation at all, but neither is confirmed explicitly enough:
– KTC M32P10 with some Innocn panel claims no PWM but since its smaller sibling does…and they also refer to the Innocn which definitely does…
– ASUS PG32UQX with the same panel as PD32M! but again here you don’t explicitly state if that’s true when local dimming is enabled.

So the issue is we’re not getting explicit enough data, and at the same time it’s rather likely that monitors with the same panel have the same backlight behavior, especially given that the LED driver is included with the panel itself.

All that being said, I actually conclude that I wouldn’t mind PWM/oscillation on a MiniLED monitor when local dimming is enabled, provided it would be able to seamlessly automatically disable when I close a HDR game or movie, without having to dance through the OSD every time.

Edit: Actually thinking of that oscillation again, isn’t the frequency so fast that each cycle is now shorter than the rise and fall times of the LEDs? After all, we’re measuring luminance of LED-excited phosphor rather than direct voltage, so PWM could easily end up looking like an oscillation.
Look at those charts: https://www.reddit.com/r/Monitors/comments/1h7jixt/phillips_evnia_32m2n6800m00_review/ – for lower brightness, the dip is wider than the peak.

[PCM2]

I’d agree that the brightness regulation behaviour demonstrated on the Philips there (good clear graphs) has some potential to be bothersome if you’re even modestly flicker-sensitive.

[Author]

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