DRAM (Synchronous Dynamic Random Access Memory) and DDR SDRAM (Double Data Rate SDRAM) are the most common types of memory found on video cards. DDR SDRAM, also known as DDR, can process information approximately twice as fast as SDRAM. There are several versions of DDR used on video cards, including DDR2, DDIR3 and GDDR3 (Graphics DDR3). The higher the number, the faster the memory chips can process information.