A Classic II makes a pretty lousy basis for comparison to an Amiga 3000; the Classic II is a *far* minimalistic machine so even if they were produced at the same "technological level" the Amiga would be bigger. Also: The Amiga probably counts as a 1989 design; it was introduced for sale in June 1990, and the 1990 date on the board probably reflects the last board revision before production. The Classic II wasn't for sale until *October 1991* so realistically there might be more than two years separating the design stages of these systems. (It's possible Apple and Commodore had different criteria for what date got silk-screened on the motherboard.)
A better comparison would be a system like, I dunno, The Mac IIci. Compared to that system the Commodore board is still much "busier", but you need to factor in that the Amiga:
A: Is still a more complicated machine, with some architectural oddities like the distinction between "chip" and "fast" RAM. (The two types are in even in physically different packages on the Amiga board; I'm curious why it uses 44256's for fast RAM but there may be some technical justification.)
B: The Amiga has *many* socketed chips on it. The IIci doesn't have any. Sockets add bulk.
The gross size of the motherboards are roughly the same, so if you factor in how much more capable (or at least, how much more complex) the Amiga is the designs look roughly "equally competent". Looking at the mainboards for other 1990 introductions from Apple, like the IIsi and IIfx, really about the most you can say is that Apple was a year or two in front of Commodore in really embracing surface mount over through-hole. If you look at Commodore's 1992 models, like the 4000/1200/600, they're all surface mount. The whole industry was switching over around the 1988-1991 timeframe, so... nothing to see here?
A better comparison would be a system like, I dunno, The Mac IIci. Compared to that system the Commodore board is still much "busier", but you need to factor in that the Amiga:
A: Is still a more complicated machine, with some architectural oddities like the distinction between "chip" and "fast" RAM. (The two types are in even in physically different packages on the Amiga board; I'm curious why it uses 44256's for fast RAM but there may be some technical justification.)
B: The Amiga has *many* socketed chips on it. The IIci doesn't have any. Sockets add bulk.
The gross size of the motherboards are roughly the same, so if you factor in how much more capable (or at least, how much more complex) the Amiga is the designs look roughly "equally competent". Looking at the mainboards for other 1990 introductions from Apple, like the IIsi and IIfx, really about the most you can say is that Apple was a year or two in front of Commodore in really embracing surface mount over through-hole. If you look at Commodore's 1992 models, like the 4000/1200/600, they're all surface mount. The whole industry was switching over around the 1988-1991 timeframe, so... nothing to see here?