A 3D semiconductor device, the device including: a first level including first single crystal transistors; and a second level including second single crystal transistors, where the first level is overlaid by the second level, where a vertical distance from the first single crystal transistors to the second single crystal transistors is less than eight microns, where the second level includes a layer transferred and bonded level, where the bonded includes oxide to oxide bonds, where the first level includes a plurality of processors, and where the second level includes a plurality of memory cells.