A absolutely great visualization of this (or at least how the execution of an instruction by the CPU is affected by memory refreshing) is this video about the S

A absolutely great visualization of this (or at least how the execution of an instruction by the CPU is affected by memory refreshing) is this video about the SNES. Video link has timecode, but it should be at 8:23. https://youtu.be/Q8ph2OVqZeM?t=504 https://youtu.be/Q8ph2OVqZeM?t=504 I find it really gives you some context. Memory is refreshed many, many times a frame, roughly once per scan line on a CRT. Edit: Though it's unclear to me if it's the CPU actually doing the refreshing or if the CPU is just waiting until the refresh is complete.