OCPC DDR5 is the newer standard, offering significantly higher speeds (4800-8800 MT/s vs. DDR4's 2133-4000 MT/s), greater bandwidth, improved power efficiency (1.1V vs. 1.2V), and higher capacity per module, with architecture changes like two 32-bit channels per module instead of one 64-bit channel. While DDR5 has higher CAS latency (CL), its faster speeds often result in similar or better real-world latency, making it superior for new builds, though it requires compatible CPUs and motherboards, unlike DDR4 which is often cheaper for budget upgrades.