DDR3 (Double Data Rate 3) is an older computer main memory technology that was widely used in the late 2000s and early 2010s. Although it has now been replaced by newer DDR4 and DDR5 memory types, DDR3 memory can still be found in older PCs and laptops. DDR3 memory can be used in a wide range of basic and older computers, but its performance is not as high as that of newer memory types.