Someone clear me up complety on this AMD 64 memory onboard thingie?

[Twista]

If the memory is onboard on the CPU now.... do i still need 3200 ram to achieve max cpu speed? I only have ddr 2100 for the time being, so would my pc still run fast as ddr3200 amd 64 machines? With amd xp machines i couldnt run 400 FSB correctly without a bad overclock so is this the case now?

 

[BitByBit]

The memory clock is determined by the processor clock and a divider, not the other way around. What's changed with the Athlon 64 is that the memory controller no longer sits between the memory and processor - it is now integrated, so it is as if there is a direct connection between the two. The memory bus speed is now determined by the clock generator, multiplied by two (DDR).
Just make sure you use a lower divider with that RAM. Zebo's overclocking guide should help you.

 

[Twista]

Originally posted by: BitByBit
The memory clock is determined by the processor clock and a divider, not the other way around. What's changed with the Athlon 64 is that the memory controller no longer sits between the memory and processor - it is now integrated, so it is as if there is a direct connection between the two. The memory bus speed is now determined by the clock generator, multiplied by two (DDR).
Just make sure you use a lower divider with that RAM. Zebo's overclocking guide should help you.

So is there really a need for ddr3200 ram? Can people now buy 2gb of DDR1600 if wanna run a NON overclocked amd 64 machine and get the same results as if with 3200 ram?

 

[BitByBit]

You could use PC1600 RAM, but you'd take a performance hit.

 

[Twista]

Originally posted by: BitByBit
You could use PC1600 RAM, but you'd take a performance hit.

thanks for the quick replies =)

So, if i use ddr1600 that will take a performace hit... than its the same for ddr2100. I minus well start saving for 2 sticks of 512 DDR3200.

 

[n7]

You could use PC2100 till you can afford PC3200 or better.

While there is a performance hit, it's much smaller than it would be on a P4 or Athlon XP.

 

[MDme]

yes there will be a performance hit. note that when you start the system up you have to set the memory divider in the bios to accomodate your slow ram. I'm not sure actually if it will post to get you to the bios but once you change the setting in the bios you should be ok. remember that you should set the divider so that when you multiply the FSB with the divider you should get the speed that your ram is rated as.

example: for PC2100 (aka DDR266) on an A64 with default FSB/HTT of 200 (your DDR clock would be 400) so you should set your divider to 133/200 or 4/6 or 2/3. that way when your system boots, your ram clock will be 200 x 2/3 which is 133 (x2 would be DDR266 or PC2100 ram) hope that makes it clear.

 

[Twista]

Originally posted by: MDme
yes there will be a performance hit. note that when you start the system up you have to set the memory divider in the bios to accomodate your slow ram. I'm not sure actually if it will post to get you to the bios but once you change the setting in the bios you should be ok. remember that you should set the divider so that when you multiply the FSB with the divider you should get the speed that your ram is rated as.

example: for PC2100 (aka DDR266) on an A64 with default FSB/HTT of 200 (your DDR clock would be 400) so you should set your divider to 133/200 or 4/6 or 2/3. that way when your system boots, your ram clock will be 200 x 2/3 which is 133 (x2 would be DDR266 or PC2100 ram) hope that makes it clear.

Cool, thanks. I have 1 stick of ddr3200 and the rest are 2100 =) Guess ill boot up with my ddr3200 1st and change the settings.