An electronic device with embedded access to a high-bandwidth, high-capacity fast-access memory includes (a) a memory circuit fabricated on a first semiconductor die, wherein the memory circuit includes numerous modular memory its, each modular memory unit having (i) a three-dimensional array of storage transistors, and (ii) a group of conductors exposed to a surface of the first semiconductor die, the group of conductors being configured for communicating control, address and data signals associated the memory unit; and (b) a logic circuit fabricated on a second semiconductor die, wherein the logic circuit also includes conductors each exposed at a surface of the second semiconductor die, wherein the first and second semiconductor dies are wafer-bonded, such that the conductors exposed at the surface of the first semiconductor die are each electrically connected to a corresponding one of the conductors exposed to the surface of the second semiconductor die. The three-dimensional array of storage transistors may be formed by NOR memory strings.