The BIU in 8088 is 8-bit data bus & 16- bit in 8086.Instruction queue is 4 byte long in 8088and 6 byte in 8086.

in 8086

instruction buffer q(ibq) is 6bytes

address bus 20 bit,data bus 16 bit

pin 28 is io'/m ' stand 4 bar.

bhe' is present.

in 8088

ibq 4 bytes

addressbus 16 bit,data bus 8 bit.

pin 28 io/m'

no bhe'