CPU/RAM compatibilty

Discussion in 'Building a new PC' started by sirfrog, Mar 14, 2009.

  1. sirfrog

    sirfrog Member

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    I am trying to figure out what RAM is compatible with a given AMD CPU. Normally, I think in terms of RAM being compatible with a motherboard, not a CPU (and of course the CPU being compatible with the motherboard). But I got a little worried when I read that the Athlon 64 X2 5050e does not support memory run at 1066 MHz but only 800 MHz. Is there a list somewhere or a way to know by looking at the specs?
     
  2. sammorris

    sammorris Senior member

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    This is because, unlike with Intels where the memory controller is on the motherboard, the Memory controller is built into the CPU instead on Athlons. If it says only 800mhz will work, odds are good only 800mhz will work.
     
  3. sirfrog

    sirfrog Member

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    Sorry, I didn't make myself clear. When I said I read that the 5050e did not support memory at 1066, I read it on a user review. I want to know where I can find this out for myself. I looked on AMDs web page but could not find anything.
     
  4. sammorris

    sammorris Senior member

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    Hmm, I'm not sure to be honest, but with AMDs, there isn't really much need to use faster memory than 800mhz anyway, there isn't much to be gained from it.
     
  5. sirfrog

    sirfrog Member

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    Yeah, I'm trying to learn a general method so I don't get burned. Like, how do I know it even supports 800 MHz? Just because 1 guy said something on a forum doesn't mean it's true. And what about other chips?
     
  6. sammorris

    sammorris Senior member

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    It definitely supports 800mhz, that's the standard RAM for such systems nowadays...
     
  7. sirfrog

    sirfrog Member

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    I was just using the 5050e as an example. I would like to know the general procedure to figure this out so I can answer questions like:

    What about the Phenom II CPUs?
    What CPUs can use 800 MHz?
    Which ones can use 1066?
    Where is the breakpoint between 800 MHz and 1066 MHz?
    Are there any that can't even use 800 MHz?

     
  8. sammorris

    sammorris Senior member

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    I don't tend to advocate many AMD systems, especially down this end, so I'm not sure, if you can't find anything googling it, perhaps ask AMD. What I do know is that the high end CPUs and Phenom IIs work with PC8500.
     
  9. jpc00

    jpc00 Guest

    I too am building an AMD system and from what I've noticed the motherboard specs will denote what memory speeds are supported. In my research I have picked up that only Phenom II's will support PC8500/1066mHz. It will usually denote that the board can support various memory speeds, but that 1066 is only available to Phenom II Class processors. So I would say to check with the board manufacturer first.
    DDR2 1066*/800
    (Due to AMD CPU limitation, DDR2 1066 is supported by AM2+/AM3 CPU for one DIMM per channel only).
     
  10. sirfrog

    sirfrog Member

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    Thanks jpc00. I started looking at motherboards on newegg and see what you mean. I see statements like, "1066MHz memory frequency with AM2+ processors only". It is kinda weird though because there are several different bus speeds associated with the AM2 line. You'd think that the faster bus speeds would correspond to a capability to handle higher speed memory.
     

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