It comes as no surprise that higher data rates allow more data to be transferred per unit of time, but there are limits to what a memory controller can support. From the term вЂњDIMMвЂќ above, a rank is the collection of ICs that connects to one of the moduleвЂ™s two 64-bit interfaces. Rank is the term the memory industry has chosen to represent what most of us think of as either banks or sides of a memory module.IC, or integrated circuit, is a term for the things most end users call вЂњchips.вЂќ A DRAM IC typically has an eight-bit interface, though some have 16-bit interfaces.DDR4 is the fourth generation of Double Data Rate memory, where each generation has added frequency, capacity, and a few other specifications to the basic standard.Because DDR data frequency is twice its clock frequency, itвЂ™s often referred to using the term MT/s (mega-transfers per second). Doubling the data rate in this manner allows (for example) a 1600 MHz wave to transfer data 3200 times per second. Clock signals resemble a square wave, and Double Data Rate simply means that data is transferred on both the rising and falling edge of the clock signal. Data Rate is the number of times per second (frequency) that a module sends and receives data.

All memory in the system is synchronized by an external clock generator. Dynamic means that each of the cells must be continuously refreshed to prevent data loss, as opposed to static memory which is typically much slower.

Random simply means that the memory controller doesnвЂ™t need to read the entire row to parse the data from the relevant column. Organized in rows and columns of cells in a similar manner to a spreadsheet (or very large table), Random Access Memory is able to access any of those cells in whatever order is instructed by the memory controller.

SDRAM stands for Synchronous Dynamic Random-Access Memory.

Some compact desktop boards use SODIMMs, typically (but not exclusively) to make room for four modules on a motherboard design that might otherwise only support two.

DIMM stands for dual inline memory module: TodayвЂ™s DIMMs have two 64-bit interfaces, one on each side, and are generally sold as either UDIMMs (aka DIMMs, long DIMMs, etc) for desktop or SODIMMs (small outline DIMMs) for notebooks.

But unless youвЂ™re working with a system thatвЂ™s several years old at this point, youвЂ™ll probably be dealing with DDR4. Most of the terms weвЂ™re using today also apply to previous generations of memory. WeвЂ™ll focus today on DDR4 because thatвЂ™s where the industry has standardized over the last four or five years.

Theoretical capacity of ddr4