From my personal notes:
"In theory, VRAM modules with similar characteristics (speed and size) should be interchangeable. The reality is that vintage Macs are much more sensitive to slight mismatches in VRAM modules than with system memory SIMMs and DIMMs. Mismatch symptoms include lines on the display, missing pixels or incorrect colours.
Apple were aware of this problem and ensured that official service or upgrade parts were the best fit for particular Mac models. For example, different service part numbers were listed for "identical" VRAM SIMMs for LCs, Quadras and 4*8 NuBus cards. Obtaining original service parts is unrealistic today, and you'll have to work around that limitation."
Alas the file that I need to check VRAM compatibility is in AppleWorks format, and AppleWorks is not installed on this Mac.
"In theory, VRAM modules with similar characteristics (speed and size) should be interchangeable. The reality is that vintage Macs are much more sensitive to slight mismatches in VRAM modules than with system memory SIMMs and DIMMs. Mismatch symptoms include lines on the display, missing pixels or incorrect colours.
Apple were aware of this problem and ensured that official service or upgrade parts were the best fit for particular Mac models. For example, different service part numbers were listed for "identical" VRAM SIMMs for LCs, Quadras and 4*8 NuBus cards. Obtaining original service parts is unrealistic today, and you'll have to work around that limitation."
Alas the file that I need to check VRAM compatibility is in AppleWorks format, and AppleWorks is not installed on this Mac.