When VRAM fails within a video device, there appear to be certain common patterns of visual artifacts. This got me thinking - when VRAM (and RAM in general) fails, what is it that's actually happening to cause these patterns?
Repeating block patterns:
Another common one seems to be a particular colour tint across a portion of the screen.
Conventional wisdom might suggest that memory devices would fail in terms of single cells, leading to isolated visual artifacts, but this does not seem to be the case. I'm interested in the common failure modes of memory used in VRAM, particularly in modern computing hardware. How does the construction of the memory device cause visual patterns such as these? What typical ways do these devices fail, leading to these "cascade" effects?