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  1. #1
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    Core i7 960 Supports a max of 24 GB of memory?

    The chip is a 64 bit chip, yet, the PAE is only 36-bits. This means it could support a max of 24 GB of memory? Ridiculous! Essentially, you have a bottle neck because the PAE will not let you use up to 64 bits of data from memory at a time which is the potential of a 64 bit chip could address, right?

    But, wait. The TLBs (memory controller) control the logical address set by the PAE. So, eventhough though your CPU can generate 36-bits of logical addresses, it doesn't mean that the memory controller is also limited to 36 bits. It can be 64 bits memory controller because the memory controller controls the page tables, and segment tables.

    Why didn't they make the chip support full 64 bit?

  2. #2
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    Re: Core i7 960 Supports a max of 24 GB of memory?

    http://en.wikipedia.org/wiki/Physical_Address_Extension

    Seems more like an OS deal, not a chipset design problem. Many chipsets and motherboards have physical limitations. Usually the OS determines what level the hardware is built to. The OS takes into account the hardware capabilities and amount of memory that will be used by the customer. Since servers can use much more memory, the boards, chipsets and OS are built to do it. Desktops use much less. 8GB is barely faster then 4. Now that cpu's are capable to 256TB that doesn't mean anyone has a use for that much memory, even if they could afford the modules.


    "The significant problems we face cannot be solved at the same level of thinking we were at when we created them."
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  3. #3
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    Re: Core i7 960 Supports a max of 24 GB of memory?

    Is it really an OS problem?

    Take a look at this

    http://ark.intel.com/Product.aspx?id=37151

  4. #4
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    Re: Core i7 960 Supports a max of 24 GB of memory?

    I would have a use for that much memory, it'd make it easier to brute force some of my CGI stuff, I.E. I could just use multiple 2048x2048 textures to make my models look better, instead of trying to tweak other settings / do stuff that's more CPU intensive.

    I'm remembering an infamous quote by the esteemed Bill Gates about no one ever needing more than 640K of computer memory.
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  5. #5
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    Re: Core i7 960 Supports a max of 24 GB of memory?

    Quote Originally Posted by cmaster View Post
    The chip is a 64 bit chip, yet, the PAE is only 36-bits. This means it could support a max of 24 GB of memory? Ridiculous! Essentially, you have a bottle neck because the PAE will not let you use up to 64 bits of data from memory at a time which is the potential of a 64 bit chip could address, right?

    But, wait. The TLBs (memory controller) control the logical address set by the PAE. So, eventhough though your CPU can generate 36-bits of logical addresses, it doesn't mean that the memory controller is also limited to 36 bits. It can be 64 bits memory controller because the memory controller controls the page tables, and segment tables.

    Why didn't they make the chip support full 64 bit?
    Artificially crippled so that businesses shell out extra cash for Xeon workstations and servers with no arbitrary memory limit?


    i5 3570k Windows 7 x64 gaming rig, Intel NUC SageTV server (2TB iSCSI storage), Intel i3 HTPC

  6. #6
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    Re: Core i7 960 Supports a max of 24 GB of memory?

    Actually they do, 40 bit addressing. You can get up to 192 GB with a dual socket board w 2 processors. 12 slots of 8GB sticks will run you 10800 bucks +/- so the board and cpus's will be cheap, relatively. God knows how much 16GB sticks are. As I said before there are other factors involved

    If you want to move freight you need a Kenworth, not an F350, if you get my drift.


    "The significant problems we face cannot be solved at the same level of thinking we were at when we created them."
    - Albert Einstein (1879-1955)

  7. #7
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    Re: Core i7 960 Supports a max of 24 GB of memory?

    I hope 8 gig sticks come down soon enough. Maybe even 6 gig sticks?
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  8. #8
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    Re: Core i7 960 Supports a max of 24 GB of memory?

    I'd settle for cheap 4 gig sticks!
    AMD FX-8350. Corsair Hydro H55. Corsair Carbide 200R. Asus M597 EVO. OCZ Agility II 256GB.

  9. #9
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    Re: Core i7 960 Supports a max of 24 GB of memory?

    Comparitively they are cheap. 12 gigs for 400 dollars for server memory. http://www.newegg.com/Product/Produc...82E16820161337
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  10. #10
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    Re: Core i7 960 Supports a max of 24 GB of memory?

    Quote Originally Posted by Windrunner View Post
    Comparitively they are cheap. 12 gigs for 400 dollars for server memory. http://www.newegg.com/Product/Produc...82E16820161337
    Yes. those are 3x4GB sticks, if you get 6 you have 24GB. the most a regular board and cpu will handle.
    If you really need more memory then that, you really also need a board that will maintain signal integrity of that much memory.


    "The significant problems we face cannot be solved at the same level of thinking we were at when we created them."
    - Albert Einstein (1879-1955)

  11. #11
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    Re: Core i7 960 Supports a max of 24 GB of memory?

    Quote Originally Posted by TheGlasMan View Post
    Yes. those are 3x4GB sticks, if you get 6 you have 24GB. the most a regular board and cpu will handle.
    If you really need more memory then that, you really also need a board that will maintain signal integrity of that much memory.
    Just wanted to clarify that PAE actually has nothing to do with the 24GB limit. It is an older technology used with 32 bit OSs to let you go beyond the 4GB limit.

    Wikipedia has a good article here:

    http://en.wikipedia.org/wiki/Physical_Address_Extension

    In a 64 bit OS such as Windows 7, PAE is not used.

    The real issue is signal integrity as Glasman has pointed out. Not PAE. Obviously if you really need more memory Intel has solutions with its Xeon/server boards but the boards are quite a bit more expensive as it is not trivial to implement > 6 memory slots. Still I have to say that 24 GB is still A LOT of memory
    *my opinions are my own and do not necessarily represent those of Intel Corp

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  12. #12
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    Re: Core i7 960 Supports a max of 24 GB of memory?

    Quote Originally Posted by Windrunner View Post
    I'm remembering an infamous quote by the esteemed Bill Gates about no one ever needing more than 640K of computer memory.
    often quoted, rarely corrected

    Q. Did you ever say, as has been widely circulated on the Internet, "640K [of RAM] ought to be enough for anybody?"
    No! That makes me so mad I can't believe it! Do you realize the pain the industry went through while the IBM PC was limited to 640K? The machine was going to be 512K at one point, and we kept pushing it up. I never said that statement–I said the opposite of that.
    as for a 24gb limit, i don't see the issue here either. if you need that much memory you probably won't be using that particular processor is my guess.
    Corsair 800D / Corsair TX750 PSU
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  13. #13
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    Re: Core i7 960 Supports a max of 24 GB of memory?

    My Q9450? Of course not!

    But a 6 core gulftown? Yeah, that's only 4 gigs a core.
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  14. #14
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    Re: Core i7 960 Supports a max of 24 GB of memory?

    Quote Originally Posted by Windrunner View Post
    My Q9450? Of course not!

    But a 6 core gulftown? Yeah, that's only 4 gigs a core.
    luckily memory isn't divided up between processor cores like that.

    more cores doesn't necessarily mean there's a need for more ram i don't think. though overall memory usage will likely go up if you are pushing all cores to their max on average.

    still the limitation is not something mere mortals are going to have an issue with.
    Corsair 800D / Corsair TX750 PSU
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