Exclusive | 2021 Apple 12.9-inch M1 iPad Pro with mini LED display shows poor display characteristics including reduced PWM and response times

The 12.9-inch Apple iPad Pro with M1 and mini LED display launched to much fanfare recently. We are currently in the process of reviewing the device but while testing, we've found some interesting results pertaining to the iPad Pro's display. Previously, we have reported on slight blur or color changes when scrolling against black backgrounds. Now, we get to study some of the display characteristics such as pulse-width modulation (PWM) and responses times of Apple's new mini LED panel.

We measured 620 nits maximum brightness (with SDR content) with our review device. At this 100% brightness, we found the pulse-width modulation to be 19.19 kHz. Going down to 75% and 50% didn't affect this value. In fact, at most brightness levels, we measured a 19.19 kHz PWM consistently. Interestingly, we see two PWM humps till at least up to 50% brightness. Only at the minimum brightness we see a single hump. This PWM pattern is very different from what we observed with the MSI Creator 17, which was the first laptop to feature a mini LED display, and also from the 2020 12.9-inch iPad Pro.

We also see that the 2020 12.9-inch iPad Pro has 207% higher PWM than the current 2021 M1 model. We expect this could be due to Apple's transition to mini LED for this generation, which may have influenced the kind of PWM controllers that Apple may have opted for. The Creator 17, on the other hand, has about 39% higher PWM. 

Despite sporting a 120 Hz refresh rate, the 2021 12.9-inch iPad Pro offers quite high response times, which may not augur well for gaming. Response times for the 2021 12.9-inch iPad Pro with M1 seem to be on the higher side at 45 ms for combined black-to-white, which is about 84% higher than what we've observed with the 2020 12.9-inch model. However, grey-to-grey response times are much better at 40 ms, which is 15% lower than the 2020 version.

We would like to indicate here that the rise and fall times for the response time measurements had to approximated as our oscilloscope had problems in reliably calculating large differences in observed brightness values due to high PWM.

Overall, while Apple's mini LED transition may work well for media consumption, there is still scope for improving some of the display characteristics, particularly the response times. We would have preferred a better PWM performance as well, though a 19 kHz PWM shouldn't be problematic for most users.

Our video below demonstrates PWM in action on the 2021 12.9-inch iPad Pro. Stay tuned for our full review of the 2021 12.9-inch iPad Pro with M1 coming soon, which will cover other aspects such as color gamut coverage, color accuracy, and more.

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