need ram advice for a dual 2.0 ghz g5

Discussion in 'Buying Tips, Advice and Discussion (archive)' started by Col127, Nov 19, 2004.

  1. Col127 macrumors 6502

    Sep 13, 2003
    hey all.

    i need some advice. i recently installed motion on my new g5 with 1 gb of ram, only to notice it lags! so i figure i should get another 1 gb of ram to help speed things up. i'm not wanting to spend too much on ram, so i was wondering which brands were okay? i used to buy kingston value ram for my g4 dp, which worked great. would kingston value ram work fine for the g5? i can get a pretty decent price at a local store in toronto.

    i'm thinking between kingston value ram, kingmax, corsair value seriees, ocz value series or micron. any suggestions? i'm leaning more towards kingston value ram since it treated me good for my g4 :p but suggestions are most welcome.
  2. zen_state macrumors member

    Nov 16, 2004
    Vancouver, British Columbia, Canada

    they recomend 2GB. at least you have double the minimum. do you have a normal pci model with a max of 4GB ram or a pci xpress with an 8GB max? you should always upgrade ram in a way that will prevent you from having to toss any sticks in the future.
  3. Col127 thread starter macrumors 6502

    Sep 13, 2003
    it can support up to 8 gb. there's no way i'm gonna double the min since i have no need for 4 gb of ram.

    i'm more looking to which brand of ram i should get, than how much i should buy.

    motion seems pretty resource heavy though.
  4. HiRez macrumors 603


    Jan 6, 2004
    Western US
    The brand of RAM you buy should not affect how much "lag" there is. It might affect whether the computer works or doesn't work, but if you're using the correct spec RAM, it should work at the same speed no matter who makes it. For a dual 2.0 GHz G5 tower, you need:

    1. PC 3200 (400 MHz DDR) RAM
    2. 184 Pin
    3. CAS 3.0 Latency
    4. Unbuffered
    5. Non-ECC
    6. Must be installed in matched pairs

    If any of these is wrong, then you're using the wrong RAM and could experience weird behavior. There's also the possibility that you're using the right kind of RAM, but it's defective. Try testing it with Rember.

    Crucial has a great reputation for Mac RAM, but I just got PNY RAM from ChumpUSA ($209 for matched 512 MB sticks) and believe it or not it all checked out and works fine.

    EDIT: Oops, had two #5s...doh!
  5. jackieonasses macrumors 6502a


    Mar 3, 2004
    the great OKLAHOMA....
    the min. is actually 512.....hard to believe huh?
  6. redAPPLE macrumors 68030


    May 7, 2002
    2 Much Infinite Loops
    can someone explain, why they have to be "paired"? correct me if i am wrong, the powermac would act weirdly if i have 2x 256 and 1x 512 ram?

    what if i have 1x 512 (bought in compusa) and 1x 512 bought from crucial? what happens?
  7. Col127 thread starter macrumors 6502

    Sep 13, 2003
    okay, so would this work:

    KVR400X64C3A/512 - Part Detail (

    **512MB 400MHz DDR PC3200 DIMM 3-3-3


    **Standard 64M X 64 Non-ECC 400MHz 184-pin Unbuffered DIMM*(SDRAM-DDR, 2.6V, CL3, Gold)

    that's kingston value ram. i'm wondering because it's 2.6V and my g5 manual says i should get 2.5V . i have no idea what the diff is.
  8. HiRez macrumors 603


    Jan 6, 2004
    Western US
    That looks like it should work. 2.6v is ok to use as well as 2.5v. The frustrating thing is that G5s can be picky about RAM, even if it meets Apple's specs, kind of like how certain CD/DVD media with the same specs will or will not work on different burners. What you have listed there will probably work fine, but I'd make sure you can return it if not, just in case.
  9. HiRez macrumors 603


    Jan 6, 2004
    Western US
    The PowerMac G5s have two separate banks of RAM, either two banks of two or two banks of four slots. Each bank provides 64-bit bandwidth from the CPU to the RAM. But, by using matching RAM in two slots in separate banks, it achieves a 128-bit bandwidth path, sort of like how a multi-drive RAID array speeds up disk access times over using a single drive.

    So, yes, it will probably act weird/slow/not at all if you aren't matching RAM sticks. Mixing RAM manufacturers between sets isn't generally a problem (provided you use properly-spec'ed RAM). For example, two Apple sticks in the first slots and two Crucial stick in the second slots). However, each pair must at the very least be matched for size and spec, and I'd say ideally they should be identical (including manufacturer). I would not recommend using the setup you list above where you only have a single 512 module. Get another identical 512 from Crucial and put it into the other bank opposite the existing one. Mixing the Crucial and CompUSA in the same pair will probably work also, again as long as the specs are correct.

    Another important thing is the physical layout of the RAM banks on the G5 motherboard. You must match your pairs to the same slot on each bank. They're laid out such that they start at the center of the two banks and sequentially move outward, like this:

    BANK 1 SLOT 4
    BANK 1 SLOT 3
    BANK 1 SLOT 2
    BANK 1 SLOT 1
    BANK 2 SLOT 1
    BANK 2 SLOT 2
    BANK 2 SLOT 3
    BANK 2 SLOT 4

    Note that this is for the Dual 2.0 models, and I believe also for the Dual 2.5s. Not sure if the 1.8s and 1.6s use the same layout. Be sure to check your owner's manual to be sure (they should have a diagram). My experience is you have to push really hard to get the RAM to seat all the way into the slot. Make sure the notch lines up, you push straight down into the motherboard, and that the securing tabs on the outside close all the way. If the RAM is even slightly misaligned or not properly seated in the slot, it won't work. Good luck.

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