Gregory's Server
Screen resolution in 1970s/80s 8-bit computers was limited by the NTSC TV standard; aka "Never Twice Same Color".
The color subcarrier frequency was 227.5x the rate of scan lines, which including horizontal blanking and some overscan gives you around 160 pixels worth of chroma in the display area.
That half pixel meant phase changed on each scan line, somewhat evening interference with the luma channel...
To make the math easier, computers and consoles usually rounded it to 228, but! -- interference now lines up on every scanline instead of going back and forth and appearing as 'checkboard' noise.
Depending on how the luma signal in higher-resolution graphics modes was phase-offset from the chroma, this meant patterns of bright high-res pixels created color artifacts very visibly and consistently.
(By "high res graphics" we mean 320 pixels across)