BenQ EX3501R 3440×1440 21:9 35″ Curved VA monitor – AMA modes (WHL #33F1)

This post is partially outdated – please have a look at the updated version #33F3 with proper photo diode measurements as well!


So…I tried measuring response time of the monitor, and I didn’t really succeed. I’m missing MY PRECIOUS photo diode, so doing the same thing with an LED…is pretty meh. Don’t take these for real, time must be off due to high capacitance (“high” being some 10pF including leads?) and the LED not being as sensitive as a proper photo sensor diode.

Well anyway, the shape of the traces tells us a little about the AMA setting of the display, which is BenQ speech for the Advanced Motion Acceleration or pixel response / panel overdrive setting. Basically this is where some magic part in the display ASIC decides how to make the transitions of each pixel from the current value to the next one before displaying the new frame. For “Off”, this seems to be a rather slow two-step process, while “High” does make that a lot faster. This may overshoot a little, but as I’m using the ghosting test with 0-255 (black-white) transition, there’s not much to overshoot. Premium on the other hand seems to try doing everything in a single step, which likely overshoots, but also offers the fastest pixel response of the three modes. This should pop out more in a grey-to-grey tests which I will do once a proper sensor is available.

The following images are taken from the AMD Windmill demo at steady 60Hz (why not 100, AMD?) at Freesync and V-Sync enabled. Camera setting 1/100s, ISO 400, f/2.8 once again.

AMA Off:

So the first one by luck captured the first step of the appearing blade, which is not as bright as it has to be. The second image shows the blade fully displayed and you can clearly see four ghosting images from the previous frames. Now that’s ugly…

AMA High:

High does a better job and is my standard setting. There’s still 3 to 4 afterimages of the blade with a tad lower intensity. The first image shows something that could be seen as active cancellation of the ghosting, but that is much more subtle than in the next setting. Also, there’s a teeny tiny hint of the next frame in the second image, isn’t it?

AMA Premium:

Premium does set the knobs to eleven. See the black first afterimage? That’s going all-in on pixel voltage, bringing down brightness as fast as possible and not giving a shit about image accuracy. It’s all about response times – displaying new things as fast as possible and deleting everything else in the same way. Note that the number of ghosting images are reduced by one, which probably requires this kind of overdrive on this type of LC panel.

Still need to make response times measurements with a photo diode…probably have to order a new one. These images above were taken at 1/100s exposure, so 4-5 images are visible in a 10ms time frame, to give you a rough clue about responsiveness of this VA monitor. BenQ claims 4ms for grey-to-grey and 12ms “tr+tf”, probably referring to the entire black-white-black transition where the first and last 10% do not count – just like measuring 0-100 km/h times with cars and subtracting the first 30cm of wheel spin of the slow to regulate ICE dinosaurs ;)

[Please see the original post and the second follow-up as well.]

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