DDR speeds

[renegade77]

Which speed DDR is the one that runs at the DDR400 speed for the nforce2 boards. Is it the pc3200 or the 3500. I dont konw much about DDR and their different speeds. Could someone help clarify.

[Gator]

266mhz = DDR2100
333mhz = DDR2700
400mhz = DDR3200 <----
466mhz = DDR3500

[renegade77]

cool, thanks!

[ALobpreis]

You just have to multiply the clock by 8 (8 bytes per clock), and the make some rounding.
So:
DDR200: 200 * 8 = 1600 -> PC1600
DDR266: 266 * 8 = 2133 -> PC2100
DDR333: 333 * 8 = 2666 -> PC2700
DDR400: 400 * 8 = 3200 -> PC3200
DDR433: 433 * 8 = 3466 -> PC3500

With the oldest Rambus, it's multiplied by 2, and with the newer, by 4.
PC800: 800 * 2 = PC1600
Later:
PC800: 800 * 4 = PC3200
PC1066: 1066 * 4 = 4266 -> PC4200 (or 4300? not much sure on this one)

DDR memory started using the naming on the right to compete against Rambus. Standard Joe goes to a shop and reads DDR266 against PC800... yeah! The 800 is bigger! :p So that's why.

[StealthHawk]

DDR PC notation actually denotes the bandwidth it supplies in single channel mode.

i have no idea what the Rambus classification is supposed to represent.

[ALobpreis]

It's its bandwidth as well!
2 or 4 bytes per clock cycle, against 8 of SDRAM.