Apple's official spec sheet say the Color Classic II has 256K of onboard VRAM. They also say the LC 550, which is supposed to use the same logic board, has 512K. How can that be? Has the knowledge base spec sheet been wrong all these years? Let's find out together.
Great article! It inspired me to check which logic board I have. Thought it might be interesting to have another data point. 🙂 My Performa 550 has the same Rev A board as you, but has a tray-loading CD-ROM drive and was manufactured in March 1994.
Thanks for the data point! Someone else contacted me and said their late 94 build had the Rev B board. My hunch is that the Rev B was introduced in Q3 1994 (June/July) but I don't have enough data to be fully confident in that position.
Plus two bonus sections about RAMDACs and the special Apple IIe video mode!