New MBP...will 555 speed ram work?

Discussion in 'MacBook Pro' started by lcseds, Nov 7, 2007.

  1. lcseds macrumors 6502a

    Jun 20, 2006
    NC, USA
    I know the system comes with PC5300-667 as that is the current memory speed for DDR2 modules. But will some slightly older PC5300-555 work?
  2. yippy macrumors 68020


    Mar 14, 2004
    Chicago, IL
    No it will not as that ram is below the system speed and cannot be up-clocked to match the system speed.
  3. tmoney468 macrumors 6502a

    Mar 13, 2007
    Wouldn't the FSB just slow down so it's in line with the Ram speed? In the PC world at least, if you have slower Ram than what your FSB is, the FSB is just reduced so it will work properly. Isn't this the case in Mac land too?
  4. CanadaRAM macrumors G5


    Oct 11, 2004
    On the Left Coast - Victoria BC Canada
    DDR2 RAM comes in 533 and 667 MHz speeds, there isn't any 555.
    If you were to install 533 MHz RAM, the machine may (or may not) work, but it would definitely be slower. There's no point to it though, because the 667 MHz modules are as cheap or cheaper than the 533's.

    Now, what you may have seen is "PC2-5300 DDR2 RAM 5-5-5"

    In that case the 5-5-5 is describing the Latency timings of the RAM module. This is the number of clock cycles that the machine must wait before doing another memory operation to that chip. 5-5-5 (or 5-5-5-12) is the standard timings for DDR2-667 MHz RAM.

    PC2-5300 and PC2-5400 are both another way of saying DDR2-667 MHz
  5. lcseds thread starter macrumors 6502a

    Jun 20, 2006
    NC, USA
    That would be good news as I have (2) 2GB modules I wanted to install in the new MPB.
    Memory label:
    Hynix 2GB 2Rx8 PC2-5300S-555-12


Share This Page