ASUS ProArt PA32UCDM Review (4K/240Hz Professional OLED)

1. Introduction2. Design3. On-screen Display (OSD)4. Panel Analysis: SDR5. Panel Analysis: HDR6. Response Times & Motion Clarity7. Input Latency8. Closing Thoughts9. View All Pages

HDR Testing

Following on from the SDR results on the previous page, here we re-test the relevant areas of the display with HDR enabled.

Modes Available

It's worth pointing out that there are a few different HDR modes available, including Dolby Vision support should you connect a suitable source. Connected to our test PC, we have the choice of two modes – HDR_PQ DCI and HDR_PQ BT.2020. We tested both, but also made sure to disable ‘Uniform Brightness', and ensured brightness was at the maximum level for both modes.

Brightness

First of all, testing both the DCI and BT.2020 modes for overall brightness reveals basically identical behaviour – it peaks at 1000 nits for the 1% and 2% APLs, before dimming as the window size increases. This behaviour is equivalent to the ‘Peak 1000 nits' modes we see from other QD-OLED gaming monitors.

Greyscale

Both modes are very similar in regards to their accuracy when using our standard 10% APL – both track the EOTF curve very well with just a small amount of roll off at the end.

However, as we've come to expect from QD-OLEDs, the EOTF curve continues to roll off early at an increasing rate as we increase the window size. The bigger the APL, the more it rolls off, resulting in an overly dark image, and this was consistent across both HDR modes tested.

As a final test, ASUS does also include three specific ‘sub-modes' within the OSD for each HDR mode – PQ Optimised, PQ Clip, and PQ Basic. The description for each is given in the manual:

• ‘PQ Optimized: Delivers the optimized HDR performance of this display with as much accuracy as with ST2084 in terms of display luminance capability.'
• ‘PQ Clip: Preserves PQ curve till displaying maximum luminance with accuracy. ST2084 code value with higher than display maximum will be mapped to the maximum luminance.'
• ‘PQ Basic: Presents HDR performance of general HDR supported displays'

I tried each of these options at a 50% APL, using both HDR_PQ DCI and HDR_PQ BT.2020 modes – for a total of six tests. However, the EOTF tracking behaviour is identical as far as I can see.

Colour Accuracy

Colour accuracy is very solid, though. The main culprits are the 100% cyan and 100% green channels, which the monitor is never going to be able to replicate accurately as it does not cover the whole Rec.2020 space.

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