One thing, though - a stock A1200 isn't much faster than an A600. It does have a 14MHz 68020 instead of the 7.1MHz 68000, but it's crippled because it has no Fast RAM. As soon as you stick a memory expansion in an A1200 it does indeed become much faster, but a stock machine you won't see much difference.
Graphics are faster, though, because of the AGA chipset.
