X4与X4m关系 更像X1与A78。ARM官方表述 Stand-alone instantiation of Cortex-X4 Low Performance Configuration ( VEC - 2x128b / L2 512K ) is prohibited. Cortex-X4 Low Performance Configuration ( VEC - 2x128b / L2 512K ) must only be used alongside at least one instance of Cortex-X4 Higher Performance Configuration ( VEC - 4x128b / L2 minimum 1M ) and always in the same cluster. Failure to comply to this requirement equals a non-compliant Arm product. For more details, please refer to the Cortex-X4 Release Note.