The SE/30 works fine with 2/3 chip SIMMs -- just checked.
Assuming 1 MByte size SIMMs, "regular" 8-chip modules use eight 1 Mbit DRAMs -- with another extra chip for parity (9 chip) modules, which simply goes unused in most Macs.
But those SIMMs with 2/3 chips use a couple 4 Mbit DRAMs (1 M x 4 bit) with an optional 1 Mbit DRAM (1 M x 1) for the parity bit, if present.
4 Mbit and larger DRAMs include a new test mode which is indeed incompatible with the circuitry of the Mac II & IIx -- that's why they need PAL SIMMs for larger capacities. These 2/3 chip SIMMs aren't compatible either. Maybe the SEs & Pluses (designed for SIMMs no larger than 1 MByte) have similar issues.
The SE/30 will work with any (fast enough) 30-pin SIMMs, be them 2, 3, 8 or 9 chip, as long as they aren't of "odd" sizes -- 2 MB and 8 MB SIMMs are not supported.
Assuming 1 MByte size SIMMs, "regular" 8-chip modules use eight 1 Mbit DRAMs -- with another extra chip for parity (9 chip) modules, which simply goes unused in most Macs.
But those SIMMs with 2/3 chips use a couple 4 Mbit DRAMs (1 M x 4 bit) with an optional 1 Mbit DRAM (1 M x 1) for the parity bit, if present.
4 Mbit and larger DRAMs include a new test mode which is indeed incompatible with the circuitry of the Mac II & IIx -- that's why they need PAL SIMMs for larger capacities. These 2/3 chip SIMMs aren't compatible either. Maybe the SEs & Pluses (designed for SIMMs no larger than 1 MByte) have similar issues.
The SE/30 will work with any (fast enough) 30-pin SIMMs, be them 2, 3, 8 or 9 chip, as long as they aren't of "odd" sizes -- 2 MB and 8 MB SIMMs are not supported.