can PM G5 DC 2.0ghz use a 677mhz ram?

imon4imon4
Posted:
in Genius Bar edited January 2014
i want a memory upgrade, so i bought the pc 5300 ram UMAX 677mhz, but my mac detect it ras a slow

3200u (400mhz?) ...and its the same whether im using UMAX / MUSKIN product



it should be pc2 5300 (677mhz) like in the macpro xeon



what im tryin to say is...is my mac working at a 400mhz or 677mhz?



even if my mac detect it as a slow 400mhz, but its still a 677 mhz architecture right?, so...

it should work as a 5300mhz right?



i need this answer fast please, cuz this next week my mac service will ask me whether i want to change it to pc24200 (533mhz) or just use the 677mhz insted...

Comments

  • Reply 1 of 9
    gwoodpeckergwoodpecker Posts: 367member
    Quote:
    Originally Posted by imon4 View Post


    i want a memory upgrade, so i bought the pc 5300 ram UMAX 677mhz, but my mac detect it ras a slow

    3200u (400mhz?) ...and its the same whether im using UMAX / MUSKIN product



    it should be pc2 5300 (677mhz) like in the macpro xeon



    what im tryin to say is...is my mac working at a 400mhz or 677mhz?



    even if my mac detect it as a slow 400mhz, but its still a 677 mhz architecture right?, so...

    it should work as a 5300mhz right?



    i need this answer fast please, cuz this next week my mac service will ask me whether i want to change it to pc24200 (533mhz) or just use the 677mhz insted...



    You need 533 MHz PC2-4200 DDR2 SDRAM for your DualCore G5. I got the same computer one year ago. Apple System Profiler reports all my RAM as "PC2-4200U-444".



    Usually, faster RAM works in a computer that has slower RAM, but there might be another problem with the RAM sticks you got. Perhaps they don't support the 533 MHz speed correctly. Personally, I would exchange them to have the correct ones.



    Oh, and no, the Mac Pro uses FB-DIMMS, which is a completely different story.
  • Reply 2 of 9
    imon4imon4 Posts: 22member
    is there a way to know whether my mac is workin at 400mhz speed or 677mhz?

    i think maybe even if it says 3200u, its just a code right?

    who know's if my mac were running at 677mhz...



    cuz no matter what, 677 mhz is better than 533...<_<

    its too bad if i change it to 533 mhz again...
  • Reply 3 of 9
    gwoodpeckergwoodpecker Posts: 367member
    One more thought: if I remember things correctly, RAM always works as fast as the slowest DIMMS installed. You'd have to install those 667 RAMs as the only ones in the system to check whether they will operate at 667 MHz at all.



    http://www.everymac.com/systems/appl..._dual_2.0.html says - as I did - that the RAM should always operate at 533 MHz.



    Usually the infos given in SystemProfiler are correct. But as I said, your RAM might be not 100% compatible with the G5, therefore working at only reduced speed.
  • Reply 4 of 9
    gwoodpeckergwoodpecker Posts: 367member
    And to be 100% sure, check also whether your machine is a true DualCore machine (Late 2005 Edition): SystemProfiler will list it as:

    Machine Name: PowerMac G5

    Machine Model: PowerMac11,2



    If it says something else, then we'd have to look at this again. There have been four 2.0 GHz G5 models so far - and only the latest one is the real "DualCore" variant.
  • Reply 5 of 9
    gwoodpeckergwoodpecker Posts: 367member
    Last thing: I just saw that you already had another thread about problems with RAM (quote: im using umax Pc2 3200u right now...cuz my 533mhz kingston is damaged after i mixed them together....i already send the kingston memory back to apple anyway.. guess i play it safe...and just use the 533mhz from apple reccomendation..).



    So two possibilites: either you still got the wrong RAM or you fried something on the mainboard with your experiments...



    So the main questions and statements are still:

    1. Exact G5 Machine model?

    2. Exact model of RAM you actually bought (PC2-3200u or PC2-5300)?

    3. Is there any other RAM installed in your machine?

    4. And you're using pairs of those RAMs, aren't you? A single one won't work!

    5. If the machine does not support 667 MHz RAM in the default config, faster RAM won't change a thing about that. The System Bus Speed (Wintel tech talk: FSB) won't change to a higher frequency as it is always 1:2 in the G5s (except for the el-cheapo SingleCore 1.8 GHz model).



    So if you would please be so kind to provide ALL the information above so we here at the forum can actually help you?
  • Reply 6 of 9
    imon4imon4 Posts: 22member
    Machine NametPower Mac G5

    Machine ModeltPowerMac11,2

    CPU TypetPowerPC G5 (1.1)

    Number Of CPUst2

    CPU Speedt2 GHz

    L2 Cache (per CPU)t1 MB

    Memoryt3 GB

    Bus Speedt1 GHz

    Boot ROM Versiont5.2.7f1



    DIMM0/J6700:



    Sizet1 GB

    TypetDDR2 SDRAM

    SpeedtPC2-3200U-288

    StatustOK

    DIMM1/J6800:



    Sizet1 GB

    TypetDDR2 SDRAM

    SpeedtPC2-3200U-288

    StatustOK

    DIMM4/J7100:



    Sizet512 MB

    TypetDDR2 SDRAM

    SpeedtPC2-3200U-288

    StatustOK

    DIMM5/J7200:



    Sizet512 MB

    TypetDDR2 SDRAM

    SpeedtPC2-3200U-288

    StatustOK

    2 slot is not working... so i only have 2 left to fill

    my RAM is all muskin, my UMAX (DDR2 64x8 DIMM 677mhz)is already sent back...

    my MUSKIN is...PC 5300 so it runs speed at 677mhz...and there are no other ram installed, only 2 pairs of muskin 1 gig and 512mb
  • Reply 7 of 9
    gwoodpeckergwoodpecker Posts: 367member
    OK, thank you for all the details. So I went to the Muskin website quickly. There I discovered that they made some mistakes in their RAM selector...



    Correct DDR2 RAM for DC 2.0, DC 2.3, Quad 2.5 G5:

    http://www.mushkin.com/doc/products/...em.asp?id=1785

    http://www.mushkin.com/doc/products/...em.asp?id=1786



    Wrong type of RAM - and no option there (G5 doesn't need ECC RAM):

    http://www.mushkin.com/doc/products/...stem.asp?id=94



    and right type, but for older G5's with DDR RAM (not DDR2):

    http://www.mushkin.com/doc/products/...stem.asp?id=92



    Now back to your problem: it seems that a lot of people have bought faster RAM for their G5 (at sales etc.) that in the end is not correctly recognized by the mainboard. That is, however, not the fault of anything in the mainboard, but rather the RAM not meeting the correct specifications. While in PC land, this might work, for the G5, very strict specifications must be met in order to having a correctly functioning machine. Cheap RAM unfortunately almost never meets the correct specifications (although I really don't know whether the list price of 140 USD per module is justified. Comparable Kingston RAM here in Switzerland costs me around 90 USD per module...).



    see other people with the PC2-3200U problem:

    http://forums.macrumors.com/showthread.php?t=205192

    http://www.kenjoy.net/files/archive-4.html



    So in the end it seems that the RAM you bought is specified for working at 667 MHz speed (PC2-5300), but does not meet the G5's standard for working at 533 MHz (the G5's default memory speed) when it's being underclocked (from 667 to 533). This is what happens then: the mainboard tests the RAM in an even slower speed (which would be 400 MHz), and there the RAM passes the test. Therefore the RAM is now working at 400 MHz instead of 533 (or 667), which consequently is displayed in the System Profiler. Don't get me wrong: the RAM will probably perfectly work and you won't even notice anything speed-wise, but I know it's strange to buy expensive memory and then not be able to use it...



    Solution: if you can, try to give back all the Mushkin memory you've bought (tell them you've tested them in various configurations and they don't work correctly) and exchange them for the ones from the two correct links above (order number 971338A, PC2-4200). Those will/should work in your G5. OR you could buy the RAM somewhere else cheaper (Kingston or Crucial make also good memory modules). But, as said before, only buy PC2-4200 modules.



    Good luck!
  • Reply 8 of 9
    imon4imon4 Posts: 22member
    Thanx a lot gwoodpecker, im gonna call my mac service, and ask for the 4200 module =p

    i hope the systm profile will display a speed of 4200u...

    if it's 3200u again, i will ask another memory until it show's 4200u
  • Reply 9 of 9
    cactusjackcactusjack Posts: 2member
    Hi,



    I have also purchased some CRUCIAL memory PC2-5300 667MHz for my PM QUAD and have noticed that the machine recognises it as PC2-3200U 288. I think I am now stuck with it as my return option has now expired. I have not noticed anything unusual with the exception of one thing - when viewing Quicktime movies on apple site, sometimes I see ghosting of the movies, and multiple threads of the player running (e.g. the viewer on the web page has image frozen while it seems another movie is playing in the background with the audio audible whilst the image itself not visible). I had never seen that effect before on any Mac, and can't tell whether its related to these memory modules. Other than that, as I said, I have not noticed anything unusual. Nor can I tell whether the machine is slower or not. Question: Should I stick with these? Would there not be any longterm effect of using these memories.

    BTW: CRUCIAL's site lists these memories as compatible with PM QUAD and makes no distinction between these and the recommended PC2-4200's.



    Regards,
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