macsforme Good thoughts! Just a theory from my side as well, but I recently noticed something after years of using swapped iPhone screens, and it lines up with what you're suggesting.
I was on hold with the tax office for about 30 minutes and, unusually, looked at the screen during the wait. What stood out was heavy banding on the default background, rough colour stepping that you wouldnāt normally see. It made me wonder if something in the software or hardware disables dithering/smoothing or whatever is responsible for smoothing gradients. Whatās interesting is that I havenāt seen this kind of banding on cheaper replacement screens before ā even though the resolution (PPI) is still high. It feels like screen swapping disables something on the software side, or the screen itself lacks support for certain features. Not sure what exactly.
Iām not picky though (if it works, itās gold, I donāt think about "better quality"), but the difference in brightness and clarity is obvious compared to my girlfriendās iPhone 14 Pro. Iāve got a 14 Plus with a knockoff screen, and the drop in quality is clear when comparing.
Another thing Iāve noticed now that winterās hit Australia (coldest in 16 years apparently, mornings down to plus 13ā15Ā°C) ā thereās visible lag on the screen when itās cold. It reminds me of early smartphone days, where everything slowed down in low temperatures. I never saw this on my previous iPhones with better knockoff LCDs and back then I lived in Europe with minus 15-20 degrees in the winter. This one reacts more like the tech from a decade ago.
From what Iāve gathered talking to a few repair shops, the Chinese started cloning iPhone screens from Gen 1. Thereās a massive range in quality (still talking about LCDs here ā OLED knockoffs are usually solid). Some LCD replacements are surprisingly good, others are awful. My guess is that the worst ones use really outdated tech, lack proper pairing, or are missing key driver support. Like running a fallback display driver on Windows when the GPU isn't recognised. Just a theory, but feels very similar.
By the way quick note on knockoff LCDs:
Good knockoffs
ā Slightly dimmer
ā A bit less sharp
ā Minor battery drain
ā Still very usable ā most wouldnāt notice unless comparing side-by-side
ā Likely still uses PWM, so may not suit PWM-sensitive people
Bad knockoffs
ā Backlight visibly flickers (though strangely it doesnāt bother my eyes)
ā Also slightly dimmer
ā A bit less sharp
ā Battery life is poor (good knockoffs perform better)
ā This particular one even started āburningā near the battery area on the screen edges ā first time Iāve seen that happen
ā Generates noticeably more heat than the better-quality replacements
ā Screen auto turn-off is weird during the phone calls (previous generations didn't have these issues).
ā Colder weather "slows down the screen"
So with all that in mind, it feels like there might be one or even multiple things happening at once, but the main pattern seems clear: swapping to a non-original screen (even an OEM one from another iPhone) seems to change the rendering pipeline in some way. Would love to hear everyone's thoughts on this.