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Thread: Let Win2k/XP use your L2 cache properly

  1. #1
    Succeded in braking Windo TZ Veteran Dehcbad25's Avatar
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    Let Win2k/XP use your L2 cache properly

    For users of Windows 2000 or XP you actually have to tell the OS what size L2 cache your processor has otherwise it won't be used properly! Luckily it's fairly easy to fix.

    Click on the Start button then go to run. From there type REGEDIT and press the "Ok" button. After it opens the Registry Editor follow this path. hkey_local_machine, System, CurrentControlSet, Control, Session Manager, Memory Management

    Once you're in the Memory Management folder look for the DWORD value
    secondleveldatacache.
    Right click on that and go to modify. Very important you have to change the Base from Hexidecimal to Decimal before modifying the values. After that's done just punch in your L2 cache size so if you're using an AthlonXP since the CPU has 256KB L2 Cache you enter 256. For Duron's enter 64 and for P4 Northwood's enter 512.
    After that's done you should notice your programs now have quite a bit more zip and the system is less sluggish because Windows now knows how to use your L2 cache properly.


    Note: You can look your CPU L2 Cache in Chipgeek
    Also it is a great site to look at techinical specifications for any CPU

  2. #2
    Triple Platinum Member Thor's Avatar
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    Nice tip/tweak, Dehcbad25. Thanks

  3. #3
    all bets are off... TZ Veteran SupaStar's Avatar
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    Thanks...Just confirmed that mine's set correctly.

    BTW - Nice link to Chipgeek. Very useful site

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    Titanium Member
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    thanks D mine was set at 0

  5. #5
    Techzonez Governor Super Moderator Conan's Avatar
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    Couldn't find any entry for "secondleveldatacache".

  6. #6
    all bets are off... TZ Veteran SupaStar's Avatar
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    Sure you do...it's right here: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management

  7. #7
    Techzonez Governor Super Moderator Conan's Avatar
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    When I enabled the tweak in Tweak XP it showed up. Had to edit it though since it changed the value to 512 instead of the proper 256.

  8. #8
    Super Moderator Super Moderator Big Booger's Avatar
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    Nice tip. So what would the value be if it were 0? Does it have some sort of default or does XP really think you have 0 bytes of L2 cache?

  9. #9
    all bets are off... TZ Veteran SupaStar's Avatar
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    Originally posted by Big Booger
    Nice tip. So what would the value be if it were 0? Does it have some sort of default or does XP really think you have 0 bytes of L2 cache?
    Not sure if XP has a default value. I have had (not now) TweakXP installed before so it's possible that it was already set from that.

    Maybe 0 is a default value - kind of like a "let windows manage my level 2 cache"

  10. #10
    Succeded in braking Windo TZ Veteran Dehcbad25's Avatar
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    sorry, I forgot one little detail. As BB pointedd out, what happens when it is "0"?
    My bad
    If it is "0" make sure you have the proper L2 value and enter it in decimal value. By default it will be Hexadecimal, so make sure you are in Decimal.
    SupaStart posted a perfect picture for it. I don't recomend using a higher value than your actual L2 because you risk to lose data.
    0 unfortunately means that XP won't use L2 cash.
    This will happen when your CPU is not recognized, so when all updates are installed you could have the right value.
    Also it is usual for AMD. Take it as you like (MS likes Intel)

  11. #11
    Titanium Member efc's Avatar
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    Nice tip. Mine was also set at 0.
    Linux Mint Debian Edition

  12. #12
    Security Intelligence TZ Veteran cash_site's Avatar
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    Originally posted by SupaStar
    Not sure if XP has a default value. I have had (not now) TweakXP installed before so it's possible that it was already set from that.

    Maybe 0 is a default value - kind of like a "let windows manage my level 2 cache"
    I think XP default is zero, cos before installed tweakxp it was zero, then after install went to 64 for my duron.

    --- 0wN3D by 3gG ---

  13. #13
    Succeded in braking Windo TZ Veteran Dehcbad25's Avatar
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    As I said it is ) if it doesn't recognize the code for the CPU. This happens when your CPU is newer than the release of the OS, or relatively new. XP uses the CPUID to get the value of the L2 Cash, so when it doesn't know how much there is, it preffers not to use it, in favor of making the system unstable.
    Lets say your value is 512 instead of 256, then the OS could crash, though with XP it tries to put the extra 256 in RAM. The drawnback is that the CPU won't recognize those extra 256, so they will get lost when you shutdown. Eventually, you coudl corrupt date, or the OS itself

  14. #14
    Near Life Experienced TZ Veteran zipp51's Avatar
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    In the modification box it is set at 200 for hexidecimal value and when I choose decimal it changes it's value to 512.I assume the 2 values are equal because if I punch in other values in the decimal form it also changes the value in hexidecimal.Is hexidecimal the default for windows to comunicate with the hardware?
    The definition of insanity is doing the same thing over and over again and expecting different results.

  15. #15
    Succeded in braking Windo TZ Veteran Dehcbad25's Avatar
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    The default value for that type of Key is hexdecimal.
    And yes, 200 hex means 512 decimal, and 100 hex means 256

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