Memory Rating

[Tuffrabbit]

Please explain the 800 MHz rating given to PC-6400 DDR2 Ram as to how it is derived and how it equates to an Intel chipset that is quad-pumped... Also, when did Intel begin using the "Quad-Pumped" architecture ?

Thanks

 

[Strebor]

Wikipedia DDR2

Like all SDRAM implementations, DDR2 stores memory in memory cells that are activated with the use of a clock signal to synchronize their operation with an external data bus. Like DDR before it, DDR2 cells transfer data both on the rising and falling edge of the clock (a technique called double pumping). The key difference between DDR and DDR2 is that in DDR2 the bus is clocked at twice the speed of the memory cells, so four words of data can be transferred per memory cell cycle. Thus, without speeding up the memory cells themselves, DDR2 can effectively operate at twice the bus speed of DDR.

And I believe Intel started quad-pumping with the Pentium 4s.