• HardwarePhone
  • Has anyone tried the Poco F4 GT? OLED screen with 1920hz PWM

I am aware of it, but I haven't seen anyone attempt to measure it with equipment.

IMO they took notice in the wrong way. They should have gone with "DC dimming", which has been demonstrated to help sensitive users, instead of cranking up the PWM rate and hoping for the best. They claim "higher is better", but this isn't necessarily true. Of course, anything is worth a try.

    a month later

    The NotebookCheck review seems to paint a different story of how the display works. Looks to possibly be just the 120Hz "refresh" of the display and not extraneous PWM. Not sure if the 1920Hz PWM is just a marketing gimmick or if it refers to some internal frequency that doesn't correlate with either the refresh frequency or PWM of the display itself.


    (You may be asking the differences between the two images. Looks to be just an altered timesacle to me.)

      JTL I am trying to understand the Notebookcheck image. If the large change in amplitude is the 120 Hz refresh rate, what is the smaller change in amplitude between refresh rate dips?

      I outlined in red (but PWM is usually completely ON-OFF and not a minor dip in brightness?):

      • JTL replied to this.

        degen I see what you mean. Truth be told I'm not sure but since it's just a zoomed in timescale I do wonder if similar artifacts can be seen with other OLED devices.

        It's worth noting that the sensor NotebookCheck uses is a "professional photodector" and not just a diode on a breadboard so that could be a factor as well.

        degen Might have mentioned this elsewhere, but someone investigating the "variable refresh rate" with the display of the Pixel 6 Pro used a Radex Lupen flicker meter but used an FFT chart, which is a plot of amplitude over frequency (frequency spectrum), whereas the traditional oscilloscope measurements are voltage over time (frequency).

        You can see how individual frequencies have a higher amplitude so it is measuring more than a single frequency.

        On a sidenote. I vaguely recall the laptop Intel sent to the "lab" with alleged differences in visual quality between two driver versions used some hardware that might have conducted a similar measurement and that was inconclusive so it might not catch all the "boogeyman" that we're interested in, but I think it would be a mistake to ignore this.

        9 days later

        I spent an awful lot of time starting at Poco F4 GT and Poco X4 Pro 5G at a phone shop yesterday.
        And to be honest I was surprised by how smooth and calm the screen looks. At times I thought it looks a bit like a photo image.
        It made me feel very optimistic after having to sell iPhone 13 pro max a couple of weeks ago due to an enormous migraine it presented me with.
        Now thinking to buy one of those Poco. Still choosing between F4 GT, X4 Pro and X4 GT (the latter has LCD screen).
        I'm also researching shops that allow returns once the phone has been switched on as in my country it's not possible.

          lifejazz

          Please keep us updated. It sucks that Poco phones have limited compatibility with US carriers but I'll switch to whatever carrier works if the phone is usable.

          I received the Unihertz Jelly 2. It's a 3 inch lcd phone. It doesn't cause the intense headaches that larger phones cause. I guess the size of the screen basically limits the amount of flickering / light / dithering that my eyes are exposed to. I'll use it for a couple of weeks as my daily phone and update with the results.

          6 days later

          The Honor Magic4 Pro has been reviewed by NotebookCheck and appears to possibly have similar dimming behavior to the Poco X4 GT. The vertical scale is a bit different so it's hard to compare waveforms.

          DishaSamir

          F4 is Amoled and X4 is LCD. It'll be interesting to see which is more comfortable for people with our issues since both phones take into account eye strain in their marketing. I wish the phones were available in a store locally for me to try out.

          Bougt Poxo F4 GT, can't use it for more than 30 mins without having a headache, I got back to my old Poco X3 Pro and no more headaches…

            4 months later

            Fenkins What have you do since then? You returned it? Or you used to it? I really care because I have Mi 11 ultra and it seems to be fatigue to me

            dev