Windows 8 and 8.1 Forums


16 GB RAM installed but only 8 GB usable

  1. #11


    Canada
    Posts : 1,950
    windows 8.1 Update 1 Pro 64bit


    Your welcome

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  2. #12


    Quote Originally Posted by Nuccii
    Usually dual channel is a kit of two modules of memory of the same size, i.e. 8GB + 8GB = 16 GB, that are placed in the proper slots on your motherboard per your owners manual. Dual channel actually works with CPU to run faster. It increases the bandwidth of transfer of information. Now, If you are using two single modules of the same size and were not part of a kit then they will operate as a single module only.
    Ummm, this is not accurate.

    Dual channel memory architecture is a motherboard feature. "Kit" is simply a marketing term for two like sticks wrapped in the same package. With modern motherboards and RAM, you can buy two single sticks (with the same specs) individually, put them in the appropriate slots and viola! - you are running in dual channel!

    While the exact same brand is preferred to ensure identical specs, today's motherboard memory controllers are very capable of making slightly dissimilar sticks work well together.

    Way back in the olden days (dual channel has been around for 50 years!!!), RAM manufacturing techniques were not as good as today. Neither were the raw materials a pure as they are today. So RAM makers actually tested each stick individually to match pairs, then wrapped those pairs in sets or "kits" in the same packaging. This is why back then, dual-channel sets cost more than buying sticks individually.

    Today, modern RAM makers no longer need to test each RAM stick individually because testing has shown the specifications for each sticking coming off the production line is well within the acceptable tolerance range to ensure compatibility. RAM making has become an extremely reliable process and this is one reason it is near impossible to find RAM that is not warranted for life. It is just that good.

    So the only reason we, as consumers need to buy RAM in dual-channel (or triple channel) "kits", is to save money. It costs less to buy in quantity. Plus less packaging is good for the environment.

    Finally, what really happens is dual channel allows the RAM to communicate between the RAM and the memory controller on each side of the "flip-flop" of the bus for "in theory", twice the bandwidth. Note that many CPUs today have memory controllers on die. Note too that theory and real world rarely jive. And they don't here either. So while you will get some performance gains with dual-channel, it will not be double.
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  3. #13


    India
    Posts : 1,536
    Win 8.1 Update x64


    Quote Originally Posted by Itaregid View Post
    ...dual channel allows the RAM to communicate between the RAM and the memory controller on each side of the "flip-flop" of the bus for "in theory", twice the bandwidth. Note that many CPUs today have memory controllers on die. ....
    Thanks for making me understand Itaregid
    One doubt though - what is 'die'?
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  4. #14


    One doubt though - what is 'die'?
    I think that came out of old printing press days. The die, in this context, is basically the surface cover of the actual CPU processor.

    See: https://en.wikipedia.org/wiki/Die_(integrated_circuit)
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  5. #15


    India
    Posts : 1,536
    Win 8.1 Update x64


    Quote Originally Posted by Itaregid View Post
    I think that came out of old printing press days. The die, in this context, is basically the surface cover of the actual CPU processor.

    See: https://en.wikipedia.org/wiki/Die_(integrated_circuit)
    That was a good read, thank you
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  6. #16


    Southern California
    Posts : 788
    Windows 8.1 Pro with Media Center x64


    If he has a dedicated 2GB GPU, how is he not able to use the full 16GB RAM? I don't recall seeing this before. Though technically, he probably won't ever need the <1GB memory he'd get if this were 'corrected'.
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  7. #17


    If he has a dedicated 2GB GPU, how is he not able to use the full 16GB RAM?
    In this case, these are not really related factors. He has a graphics card, not integrated. But even if integrated, it would not take away 8Gb.
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  8. #18


    Southern California
    Posts : 788
    Windows 8.1 Pro with Media Center x64


    Quote Originally Posted by Itaregid View Post
    If he has a dedicated 2GB GPU, how is he not able to use the full 16GB RAM?
    In this case, these are not really related factors. He has a graphics card, not integrated. But even if integrated, it would not take away 8Gb.
    Yep, that was really strange.

    With an integrated GPU, it usually reserves only a small amount for itself. In this case, he has a dedicated card, and it is still reserving some memory. I am curious why he isn't able to obtain the full 16GB. Limitations of the memory itself, or need of more memory for the card, perhaps?
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16 GB RAM installed but only 8 GB usable
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