Question: is all ddr4 ram sdram?
Answer: Not all SDRAM is DDR4 SDRAM, not all DRAM is SDRAM, and not all RAM is DRAM. DDR4 SDRAM is the 4th generation of JEDEC DDR SDRAM and the 5th generation of SDRAM which includes the original 3.3 volt SDRAM (now commonly referred to SDR SDRAM).