The Apple M2, introduced in 2022, and the Apple M4, launched in 2024, are both ARM-based system-on-chip (SoC) designs featuring unified memory architecture. That is, they use the same memory for both graphics (GPU) and main computations (CPU). The M2 processor relies on LPDDR5 memory whereas the M4 relies on LPDDR5X which should provide slightly more bandwidth.