PPI (Pixel Density)

PPI is pixels per inch: the same 1080p resolution is far sharper on a 6-inch screen than a 7-inch one, which is why raw resolution alone does not tell you sharpness. On small handheld screens even 720p can look crisp at typical viewing distance. Higher PPI looks nicer but costs performance and battery to drive, so on a handheld there is a real sweet spot — chasing maximum resolution on a small panel often spends power for sharpness your eyes barely resolve.