You often see companies advertising their RAM as operating at a given MHz (Megahertz Per Second). While other companies advertise their RAM as operating at a given MT/s (Mega Transfers Per second). You may begin to wonder, is MT/s the same as MHz? or if not, what is the difference?
Meaning of MT/s and MHz
Mega Transfers Per Second abbreviated MT/s is a measurement of bus and channel speed in millions of “effective” cycles per second. While, Megahertz Per Second, abbreviated MHz means one million cycles per second and is used to measure the transmission speed of electronic devices. By their definitions, it is easy to see how MT/s and MHz could be confused.
The Difference between MT/s and MHz
The main difference between MHz and MT/s can be derived from DDR (Double Data Rate). DDR or Double Data Rate is a type of memory. As its name implies, DDR provides double the data transfer rate compared to how many cycles it completes.
This means that a 2666 MT/s DDR4 stick of RAM actually operates at a base speed or frequency of 1333 MHz. However, due to it completing double or two operations per cycle, it operates as if its frequency is 2666 MHz. But this is technically not correct because MT/s properly represents the actual number of transfer operations that occur rather than the frequency in MHz. MT/s is essentially the effective MHz and should be used rather than MHz.