Gradient problem on the Asus ROG Swift OLED PG32UCDMZ 32" (firmware MCM109)

[RandomTux]

Hi, I just purchased the Asus ROG Swift OLED PG32UCDMZ 32", which I understand is more or less the same panel as the PG32UCDM.

Everything seems fine otherwise, but I'm noticing a particular kind of banding that seems brightness/gamma/tone specific. (Ie. not the common vertical banding visible on dark grays.)

There's this "bump" in brightness in gradient in a specific spot. Affects color gradients too.

• If I change the display's gamma setting, the bump moves accordingly
• It happens in a diagonal gradient as well, as seen in the other photo
• It's not a particular area of the screen; if I move the test image, the "bump" moves along with the image

Photos exaggerate the issue to some degree, as always, but I'm kind of curious as to whether my panel's defective, as reviews for the PG32UCDM specifically show a smooth gradient without such issues.

Things that DON'T affect it:

• 10-bit vs 8-bit color
• Windows's color management
• novideo_srgb clamp and custom dithering settings
• Refresh rate
• DSC on/off

My second monitor's an Asus XG27AQDM; if I drag the example images there, there's no such pronounced bump.

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Is this something that affects all PG32UCDMZ 32" units (and/or MCM109)? If so, is it something that might be fixed in upcoming firmware updates?

If not, I'm tempted to return my purchase, as the gradient issue also affects actual content, making shadows on faces have sharp edges etc.

[Hexenkartothek]

I have the XG32UCWG and have similar gradient issues so I wouldn't hold your breath. 

[swing-john]

That kind of “gamma-locked” bump moving with the gradient usually points to tone mapping / EOTF behavior rather than spatial uniformity or panel damage. Since it follows the image and shifts with gamma, it’s unlikely to be a defective area of the panel itself.

One thing that helps isolate this is checking ultra-smooth full-screen gradients at fixed luminance steps (no OS color management involved). I’ve been using pinkscreen.org (screen test) to verify whether the transition is uniform across different gamma curves and color channels.

If the bump shows up consistently at the same relative code values, it’s probably firmware LUT behavior rather than a bad panel.