I have four identical displays I purchased on Amazon:
One of them is visibly flickering, making the display very unpleasant. I took a "slo-mo" video with my iPhone. If you watch this video on YouTube at 0.5x speed you can see one bad display (the one on the far right) seems to be refreshing way faster than the other three:
In this video, all four displays are wired in parallel to a single SPI bus coming of a Raspberry Pi 3.
I admit, I have already had to return one of these displays to the seller and get a replacement. So they may just be janky. BUT, before I throw these out AGAIN, I just wanted to see if anyone knows how to fix the problem.
I'm using a library forked from Adafruit:
...and I've tried tweaking the SPEED_HZ value from 2000000 up to 8000000 without noticing any visible change.