 As a microarchitecture, the 68030 is basically a 68020 core with an additional 256 byte data cache and a process shrink and an added burst mode for the caches, where four longwords can be placed in the cache without further CPU intervention.Motorola used the process shrink to pack more hardware on the die; in this case it was the MMU, which mostly (but not completely) compatible with the external 68851.The integration of the MMU made it more cost-effective than the 68020 with an external MMU; it also allowed the 68030 to access memory one cycle faster than a 68020/68851 combo.