ddr2 confusion

[m3rcury]

So, in the good old days of DDR memory, one simply had to take the fsb of the processor (lets use amd chips), multiply by 2, and you'd get the optimal ddr speed.


Athlon XP with 133mhz fsb = ddr 266
Athlon XP with 166mhz fsb = ddr 333
Athlon XP with 200mhz fsb = ddr 400

... and so on.

Now with AM2 socket and the new fangled ddr2 technology, I'm slightly confused. Do we still use the same rule?

Athlon X2 3800+ with 200mhz fsb = ddr2-400 ? (which is pc2-3200?)

But then there's ddr2-667 and ddr-533 and a truckload other options.

I tried googling and even looked up AMD's website. They say everything from ddr-400 to ddr-667 is supported by the on die memory controller. So... what speed is "normal" ?

(Note: replace 'fsb' with 'htt'. yes i know there's no real 'fsb' with the k8 arch)

 

[m3rcury]

Right. Well that settles that.

 

[CalvinHobbes]

http://en.wikipedia.org/wiki/DDR2

 

[n7]

Higher memory frequency = high bandwidth = better performance.

That's why we have all kinds of options these days.

Default 1:1 speed for AM2 would be DDR2-400, except that there's no such thing as 1:1 on A64 architechture. And DDR2-400 is damn slow.
Better options are DDR2-533/667/800, etc.