AMD64x2 speed v.s. DDR2 memory speed?

Can someone explain 64x2 processor and memory speed combinations. Is it
correct to assume any 64x2 processor speed will work with any memory speed
except at possibly reduced efficiency? What are the max processor speeds
what till run with each of the following DDR-800, DDR-667, and DDR -533?

I will use an Asus M2A-VM motherboard.

Joe101 wrote:
> Can someone explain 64x2 processor and memory speed combinations. Is it
> correct to assume any 64x2 processor speed will work with any memory speed
> except at possibly reduced efficiency? What are the max processor speeds
> what till run with each of the following DDR-800, DDR-667, and DDR -533?
>
> I will use an Asus M2A-VM motherboard.
>
>

*******
http://icrontic.com/articles/amd_socket_am2_review

Default memory division for socket AM2 processors:
CPU Frequency Memory Divisor (For DDR2-800) Resulting Memory Frequency
2800MHz CPU/7 400MHz <--- 400*2 = DDR2-800, correct
2600MHz CPU/7 371MHz <--- 371*2 = DDR2-742, slower than normal for DDR2-800
2400MHz CPU/6 400MHz
2200MHz CPU/6 367MHz
2000MHz CPU/5 400MHz

CPU Frequency Memory Divisor (For DDR2-667) Resulting Memory Frequency
2800MHz CPU/9 311MHz
2600MHz CPU/8 325MHz
2400MHz CPU/8 300MHz
2200MHz CPU/7 314MHz
2000MHz CPU/6 333MHz
1800MHz CPU/6 300MHz

As you can see above, the default memory frequencies can vary from processor
to processor. Only the 2000MHz models appear to be able to run at the correct
400MHz and 333MHz memory clocks. Although it is unfortunate to have lost
consistency across all models, the largest delta seems to be only 33MHz.
In the grand scheme of things, that will not amount to much in terms of
'real world' performance. It will be interesting to see if/how AMD tries to
address this in future processor revisions.
*******

The Divisor selected is such, that the memory is not forced to run
faster than its spec. In other words, both DDR2-800 actual running
rate, and DDR2-742 actual running rate, are both acceptable for a
product rated at DDR2-800. They don't want to overclock the RAM, for
people who don't believe in overclocking their hardware. The default
is to keep the product within specs.

Note that if you raise the CPU clock from its normal 200MHz value, that
overclocks both the CPU and the memory. They are all tied together,
and the user is responsible for turning down the memory, if overclocking
the CPU.

HTH,
Paul