RAM

Discussion in 'Computers & Website Forum' started by MISSIONARY, May 24, 2004.

  1. MISSIONARY

    MISSIONARY
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    I installed 256 memory in my computer. I already had 128 so I thought that these two would add up to 384 but my computer info says I have only 240.

    Help! :confused:
     
  2. rsr

    rsr
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    Make sure the new memory is compatible with the old. Try switching the location of the RAM; depending on your configuration, that can affect how the computer recognizes memory. What is the total amount of memory your machine can access?
     
  3. Trotter

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    Also, your computer may be telling you how much memory yuo have minus what Windows is gobbling up. At least, that's how mine does it.

    Here's a link for a handy little program that happens to be free. It is Belarc Advisor. It will scan your machine and give you a printable list of everything, and I do mean everything, in it.

    Belarc Advisor Download Page

    I have found that it can be a lifesaver in many situations. Download it, run it, and print out the results. Put these up in a safe place, because you never know when something could go splat inside your beige box!

    In Christ,
    Trotter
     
  4. SpiritualMadMan

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    What version of 'Windows' are you running?

    I had a similar problem with an older board I had, worked fine with PC100 Dimms but the BIOS wasn't smart enough to know what to do with PC133!

    Sometimes it would count some of the memory... Sometimes none at all... Finally got another PC100 dimm and it counted properly...

    You also didn't say what kind of computer you had... I am assuming it is a newer one with 168 pin dimm or DDR in it?

    Even in WinXP there is a 'Mem' command that can be run from a Command Prompt (DOS Window). That will give you even more info.

    Use /d or /c to get different readouts and how memory is being used.

    In a Win98 use /p to page the screen... /p has a different use in WinXP as paging is not needed.

    Also, you can right-click on 'My Computer' and select properties and it should tell you how much Windows thinks it has to play with...

    What 'style' of memory slots do you have in your system? I have a few boards that have a 168 pin dimm and 72 pin simm mix... Have to be *real* careful how memory is mixed.
     
  5. Johnv

    Johnv
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    Older memory would often have to be installed in pairs. For example, to install 128mb, you'd have to install two 64mb DIMMs (dual inline memory module). How old is your system? Perhaps your new memory is conflicting with the old memory. Try rearranging the memory in differrent slots.

    PS - In newer machines, this is not the case, and SIMM (single inline memory module) is more than adequate.
     
  6. SpiritualMadMan

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    Quick Recap:

    72 pin simm memory is 32 bits wide... (36 if it has ECC) And, in a 64 bit memory bus has to be installed in *matching* pairs...

    Generally rated in nano-seconds of access time.

    Without wait states...

    a 66 Mhz bus could work with say 10nSec simm (assuming a 5nSec overhead)

    a 75 Mhz bus could work with say 9nSec simm's 4nSec overhead.

    a 100 Mhz bus could work with 7-8nsec simm's
    (I've seen them this fast)

    a 133 Mhz bus would require 5-6nSec simm's
    (I have not seen them this fast.)

    depending upon the 'overhead' of the motherboard you might get away with a slower than recommended speed.

    But, it may or may not react fast enough across the full temperature range... Or, the entire simm.


    168 pin dimm memory is 64 bits wide... (72 if it has ECC) and is adequate 'stand-alone' for existing processors... (Though a performance boost can occur if your board supports memory interleaving and you install two *matching* dimms)

    Generally rated as PC-66; PC-100 & PC-133

    DDR is 184 pins and can not be mixed with the previous two styles of memory. (Though some motherboards do have slots for both.)

    72 pin simm do not have a serial eeprom device to tell the system what they are.

    With Dimms, they have information in a seriall eprom device that the processor looks at at boot...

    If the BIOS doesn't know what the coded information means it won't set up the memory controller correctly...

    The dimm may or may not work... May or may not work completely across it's memory range.

    Very few motherboards have provisions to override what they 'see' from the eprom device...

    Those that do... Do not document them very well...

    But, *all* this is conjecture without more information...

    One more thing... SDRAM Dimm came in 5v and 3.3 volt versions... If the voltage is set wrong it could also affect the dimms ability to operate across it's full memory range.

    Usually there is a jumper for each dimm slot... Though some systems auto-detect...
     
  7. Trotter

    Trotter
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    Belarc Advisor will give you the name of your motherboard, and its manufacturer. With this information, you can go to their website and look up exactly what type of memory it should use, how much memory it can support, and up to what speed processor it can handle.

    Like I said, it is a lifesaver!

    In Christ,
    Trotter
     
  8. SpiritualMadMan

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    Trotter is right!


    BelArc Adviser is an awesome program!!!


    Too bad the license doesn't allow it to be used at work!
     
  9. Trotter

    Trotter
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    But you just can't beat the price...
     
  10. MISSIONARY

    MISSIONARY
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    I am not high tech computer. But I can tell you I have XP Professional. If there is something I can do I will have to led through it with precise step by step instructions.
     
  11. MISSIONARY

    MISSIONARY
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    BTW
    I installed Belarc, pretty cool. It says that I have installed on my computer 386 RAM
    slot "0" has 128 and slot "1" has 256

    Now does this mean that it is functioning as it should?
     
  12. SpiritualMadMan

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    Apparently BelArc found *all* the memory...

    'Which' computer info says it's only 240 MB

    Is that listed as 'physical' RAM

    In [My Computer] [System Properties] [General] near the bottom it should list how much RAM is installed...

    If it doesn't agree with BelArc... We'll have to scratch our heads a bit more.... [​IMG]
     
  13. Trotter

    Trotter
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    Missionary,

    Using the info Advisor gave you, go to the website of your motherboard's manufacturer. Find your model number and read the specs. You might have mis-matched memory types.

    If you have, hopefully you can swap it for the right type. If not, maybe you will know someone who would be willing to trade.

    When I upgraded my RAM, I added a stick of 256 to my existing 128. Later, I bought another stick of 256, and swapped it for the 128. A friend at church had a similar computer, so I gave him the 128 (and installed it for him). He then bought a 512 and swapped it out for one of the 128's, so he now has 640MB.

    Come to think of it, he had some trouble with his RAM at first, but after we pulled it out and reseated it, it was fine. Worth a shot.

    In Christ,
    Trotter
     
  14. MISSIONARY

    MISSIONARY
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    i dont know what happened or where i originally read the 240 figure but i went to my computer and it says i have 386. so i guess i am ok

    told you i was a little dumb on the computer side

    but thanks to you i have all the stats for my computer.
     
  15. Trotter

    Trotter
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    Missionary,

    Ain't God great? He already had everything worked out. And, somewhere down the road, you will probably need those stats.

    In Christ,
    Trotter
     

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