Pumping (computer systems)

[1] Early types of system memory (RAM), such as SDRAM, transmitted data on only the rising edge of the clock signal.

However, quad-pumping has been used for a while for the front-side bus (FSB) of a computer system.

Intel computer systems (and others) use this technology to reach effective FSB speeds of 1600 MT/s (million transfers per second), even though the FSB clock speed is only 400 MHz (cycles per second).

[1] Example: A Core 2 Duo E6600 processor is listed as 2.4 GHz with a 1066 MHz FSB.

The DDR2 RAM that it is compatible with is known to be double-pumped and to have an Input/Output Bus twice that of the true FSB frequency (effectively transferring data 4 times a clock cycle), so to run the system synchronously (see front-side bus) the type of RAM that is appropriate is quadruple 266 MHz, or DDR2-1066 (PC2-8400 or PC2-8500, depending on the manufacturer's labeling.