A 386SX processor has 16-bits and 386DX has 32-bits
to emphasize that it was a 4 bit processor
Intel 4004
4004 is my guess (1971).
The i7 is a 64 bit processor.
The first microprocessor was the 4004. It could handle 4 bits at a time.
The Intel 4004 introduced in 1970 and was the first processor introduced by Intel.
8086 is a 16bit processor.
16
The 386DX is a 32 bit processor running on a 32 bit bus.
The 386SX is a 32 bit processor running on a 16 bit bus.
Either Intel 4004 (commercial 1971) or F-14 processor chipset (military 1969 & classified until long after 4004 was obsolete).