G5 iMac Memory Upgrade for Newbie

bigberthabigbertha
Posted:
in Current Mac Hardware edited January 2014
I bought a "stock" 1.8 G5 iMac last week. It only has 256MB of RAM. I'd like to buy two 512MB sticks from TigerDirect.ca (yes, I'm Canadian). Will this suffice:

Ultra DDR Memory

Comments

  • Reply 1 of 6
    gmacgmac Posts: 79member
    Quote:

    Originally posted by BIGBERTHA

    I bought a "stock" 1.8 G5 iMac last week. It only has 256MB of RAM. I'd like to buy two 512MB sticks from TigerDirect.ca (yes, I'm Canadian). Will this suffice:

    Ultra DDR Memory



    Yip that'll do it. No mention of CAS latency timing in the specs, but if you're buying two of these, they should match each other and you'll benefit from 128 bit memory access
  • Reply 2 of 6
    bigberthabigbertha Posts: 5member
    Quote:

    Originally posted by Gmac

    Yip that'll do it. No mention of CAS latency timing in the specs, but if you're buying two of these, they should match each other and you'll benefit from 128 bit memory access



    CAS latency timing???
  • Reply 3 of 6
    gmacgmac Posts: 79member
    Quote:

    Originally posted by BIGBERTHA

    CAS latency timing???



    CAS is Column Address Strobe (there's also RAS - Row Address Strobe). Basically it's how RAM is addressed and accessed by a memory control. Think of RAM as a grid of bits of data. When you want to read a bit, you have to supply the row and column to find where the bit is in the grid. There is a delay from when the column address is strobed until the column data can be read - the shorter the delay the faster the memory.



    When an iMAc G5 has two memory sticks of the same size and same CAS timing, then the iMac will be able to address the memory as a full 128-bit path rather than 64-bits if they didn't match. this will yield better performance.



    You'll see CAS latency represented as CL in specs for memory and will have a number like 2, 2.5, 3, etc.
  • Reply 4 of 6
    alephaleph Posts: 15member
    So, if I understand it correctly, installing 2*512 MB RAM gives me a faster computer then 1*1024 MB due to the 128 bit bus.



    Another question: the iMac can be upgraded to 2 GB. Is there any use for that? I mean, is it a huge advantage over 1 GB? One 1 GB module cost a lot more than two 512 MBs.



    I am just finding out how much RAM (and in what configuration) I will put into my newly ordered iMac.
  • Reply 5 of 6
    dinodino Posts: 34member
    Wow. I never knew there was a tigerdirect.ca.
  • Reply 6 of 6
    copocopo Posts: 10member
    I have heard of the "compatability" of RAM chips on the stick with the G5s. The staff in the local store told me that they only use RAM sticks with Samsung chips, some of the Kingston DDR400 use Samsung memorys on Kingston boards. So far they don't have any problem with these memory with the iMac G5s.



    My 20" will arrive within this week, I have bought a pair of original Samsung 512MB DDR400 CL3, which is made by Samsung from the chips to the board. I have it tested to run on my PC and they works. I'll have it report after my iMac arrived and installed the RAM.



    Cheers,
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