LIFTING THE LID ON DDR5.

As manufacturing processes have improved, DDR data densities have increased, enabling computers to support ever-growing RAM allocations without requiring huge numbers of memory slots or dozens of chips soldered onto the motherboard. Although DDR5 has the same number of total contacts, the notch is in a slightly different place, so it's impossible to force a DDR4 module into a DDR5 slot, or vice versa. However, a single 16GB DDR5-6400 DIMM will currently set you back around $280, while a 16GB DDR4-2133 module can be had for $58, so whether it's worth the money is another question entirely. [Extracted from the article]