Who's to blame?

Discussion in 'iMac' started by iDarbert, Feb 12, 2008.

  1. iDarbert macrumors regular

    Joined:
    Feb 12, 2008
    #1
    Hello everyone, this is a little hard for me to explain what's going on but I'll do my best hoping someone can help me figure this out.

    A few weeks ago I decided to buy 3Gb of RAM for my Intel C2D iMac (24", 2.16Ghz).
    I went to a local shop and they gave me generic laptop memory with the right frequency (667Mhz) which were supposedly "certified to work in Macs" in the form of memory banks: a "brand" Kingston 1Gb bank and a "non-brand" Transcend 2Gb block.

    As soon as I tried to install in I noticed they were hard to both insert and extract from the iMacs slots (as opposed to the two original 512Mb blocks, which can be inserted and removed easly).
    They are particularly hard to extract, and most of the time they require to be "pushed" out by using a small screwdriver on the sides like a lever, while the stock 512Mb simply "pop out when the two rubber things are pulled, they also appear to be slightly thicker than the stock RAM.

    I decided not to pay much attention to that, and started using the boosted Mac.

    I nearly immediately noticed some issues in the form of artifacts in video and UI, either in the form of black squares inside buttons or Finder filename labels or weird lines in videos which were either green or formed by multicolored pixels.
    I also experienced somewhat-frequent weird lockups in which the whole screen would basically freeze, but the cursor would still move, and everything would come back normal after half a minute or more.

    I ignored such signs for a while, then I tried playing Feral's port of the game "The Movies", and was greeted by artifacts allover the game ("regular" 3D artifacts, polygons stretching out and covering most of the screen, flashing textures, etc. etc.).

    So I decided to test various combinations of RAM banks, and I noticed that while the system (and particularly the game) works better without the 2Gb "non-brand" RAM it still locks up after 15 minutes or so inside the game.
    This lock up is also partial, I can still move to cursor around and I can hear the games' sounds, and the cursor can move and change in shape when it hovers where a game element should be, but the picture in the screen stands still.
    After using the shortcut to force quit the frontmost application, The Movies closes, but the screen is either filled by garbage (lots of colored pixels) or a black screen with only the cursor working in a spinning beachball or regular cursor if moved outside a region that I assume being the game's aread.

    My hot corner for putting the display to sleep also works if the cursor is placed there, and I can even put the iMac to sleep using the power button; however when waked up the screen doesn't show anything else than the cursor.

    I have no idea how the rest of the system works without the new RAM, the other problems usually manifested after intense use of the Mac which I'm currently unable to reproduce.

    Being such the case, I don't really know who else to blame; the RAM is the one that came with the iMac so it shouldn't be the issue, but I'm pretty confident that 2Gb bank does not work properly.
    In the other hand the issues with The Movies seem GPU related, so either the GPU can't handle the game (which I doubt) or it's dying.

    I don't really know what else to think, this whole matter is confusing me in a way I was never confused before.

    Thanks in advance
     
  2. TEG macrumors 604

    TEG

    Joined:
    Jan 21, 2002
    Location:
    Langley, Washington
    #2
    You obviously have the wrong RAM installed (too slow). Put the original RAM back in the iMac and see what happens.

    TEG
     
  3. iDarbert thread starter macrumors regular

    Joined:
    Feb 12, 2008
    #3
    I've tried, and the result (as long as The Movies is concerned) is still the same, except for the artifacts which don't seem to appear anymore, but the lockups still take place.

    The frequency is also the same in every bank (stock, 1Gb and 2Gb), so I'd really exclude the RAM being faulty.
     
  4. TEG macrumors 604

    TEG

    Joined:
    Jan 21, 2002
    Location:
    Langley, Washington
    #4
    Call Apple Care, and don't tell them about the new RAM.

    TEG
     
  5. iDarbert thread starter macrumors regular

    Joined:
    Feb 12, 2008
    #5
    My Mac isn't under warranty anymore, it's already 1 year and 4 months old.
     

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