Powermac G5 DDR2 Dual core ram

Discussion in 'Macintosh Computers' started by mashinhead, Oct 28, 2005.

  1. macrumors 68020

    Joined:
    Oct 7, 2003
    #1
  2. macrumors 6502

    Mhaddy

    Joined:
    Oct 26, 2005
    Location:
    Canada
    #2
    There's a thread just like this one with a similar question. The RAM in the new PowerMac's are of the 4200 variety, not the 5300. As such, while the 5300 may work, you won't be able to take advantage of its faster timing. I just bought the 512MB 4200 from Crucial for my recently shipped 2.0DC PowerMac. That's what's currently in it, so that's what I bought.
     
  3. macrumors G3

    Joined:
    Jul 23, 2002
    Location:
    Sol III - Terra
    #3
    Actually it's the faster bus speed that doesn't matter. the PC 4200 at CL=4 has a faster clock speed.
    The PC 5300 is CL=5. The higher the CL number, the slower that ram (at the same bus speed).
     
  4. macrumors member

    Joined:
    Oct 24, 2005
    Location:
    Kansas
    #4
    Ram for new dual core 2.0 GHz

    I just recieved my new dual core on Monday and I installed two Corsair VS1GBKIT533D2 1GB Kit DDR2-533 PC2-4200 Value Select kits. The system has been working flawlessly for many hours this week. Depending on how much RAM you want in the future, you might consider using 1GB sticks instead of 512MB.
     
  5. macrumors G5

    CanadaRAM

    Joined:
    Oct 11, 2004
    Location:
    On the Left Coast - Victoria BC Canada
    #5
    The clock speed that the RAM is rated to handle is PC4200=533 MHz and PC5300 = 667 MHz --- but the Mac will run it at 533 MHz regardless. The term CL stands for CAS (Column Address Strobe) Latency; in brief it is the number of clock ticks that a given bank of memory has to wait to "recharge" before it is ready to do another memory operation.

    CAS Latency does have an effect on performance, you are quite correct on that, all else being equal, a higher CAS latency means fewer memory operations per second, because the machine spends more time twiddling its thumbs waiting for the memory. While a higher latency will slow the machine down, there is no evidence at this stage that Apple has engineered Mac motherboards to take advantage of lower latency modules. Apple says essentially nothing about the subject other than they 'support' RAM with a range of latency settings. Now a RAM module that does CL 5 at 667 MHz shoudl probably handle CL4 at the 533 MHz speed that the Mac will run it.

    So spending more for low latency RAM is 'probably' not worth it on a Mac. Spending money on higher speed (667 MHz vs. 533 MHz) RAM is definitely not worth it.

    Thanks
    Trevor
    CanadaRAM.com
     
  6. macrumors 6502

    Mhaddy

    Joined:
    Oct 26, 2005
    Location:
    Canada
    #6
    You got yours already? Damn, shipping to Canada always takes longer ;).

    Why'd you decide on Corsair over Crucial?
     

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