Memory vs CPU speed

I recently fitted an AMD XP 3200+ 2.2GHz 400FSB and 400DDR ram on an abit nf7 v2 board. The system is unstable at 400MHz between memory and cpu so I have changed the memory to cpu speed to 333MHz. The cpu internal and extrenal clock speed is still 200 x 11 = 2200 but if the memory is running at 333 does this mean the cpu is effectively running at 11 x 166 = 1800?

 

Hi,

Set the fsb to 200 the multiplyer x 11 and the ram clock at 200. This is correct for your mobo, cpu and ram and will run the ram insync with the cpu for greatest stability. If these settings don't work then time to start looking elseware. What are your temps? Have you tested the ram?

Rick

 

Thanks.. Its running stable at mem speed of 200Mhz. I read another article which confirms the 200 speed, but I got an email from AMD helpdesk today (i asked them last week). This is what their guy says:

"please keep in mind that for this processor to operate correctly at full speed you will need PC3200 memory, lower speed memory will cause problems"

I don't understand this. Doesn't the guy at AMD know what he's talking about?

 

Well that depends on the content of the email you sent him. What ram do you have is it pc3200,pc2700 or something else? If you had your ram clock set to spd then bios reads what ram you have and sets the ram clock accordingly, so if you have pc2700 then the ram clock would get set to 166x2=333. If the fsb is 200 then the ram and cpu are running out of sync this can but not always lead to instability. If you have pc2700 ram there are two solutions, either underclock the cpu by running it 166x11 witch is not taking advantage of the full cpu speed or overclock the ram by setting the ram clock to 200 if it works. It is not uncommon to run out of sync but when not stable its one of the first things to try. Best way I can explain I hope I am clear enough. Anyway glad you are stable and thanks for reporting back your results as not everyone does.

Rick

 

I have PC3200 which the board detects as 400MHz. I have set it manually at 200MHz and it is stable, but I don't know if 200MHz is actually only using the ram as 100ddr or if it is in fact 200ddr = matching the xp 3200 FSB of 200 double rate, which the board reports as 400FSB. I suspect I'm going at half speed so Im sending the ram stick back for a replacement. I wish someone would take a big stick to these guys and make them all report and talk in the same numbers. Thanks for your help.

 

No your settings are correct the ram is running at its rated speed 200x2 =400mhz just like your cpu 200x2= 400 you are not running at half speed. The reason you were unstable was because of incorrect settings, all will be good now

Rick