Jan 262008

Every CPU nowerday's has Level 1 cache memory and Level 2 cache memory which enables the core of the cpu to take pieces from the main DDR system memory and calculate with it, then store it back , the size of your L2 cache can be set in the registry of Vista and for some reason it seems that Vista isn't doing this by default.

The registry key where Vista stores the size o

f your L2 cache is

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management

Here you will see a key called SecondLevelDataCache with a value of 0 which means that windows Vista didn't set the memory size of the L2 cache by itself.

The following values can be set for DWORD:SecondLevelDataCache

256KB: 100 hex
512KB: 200 hex
1024KB: 400 hex
2048KB: 800 hex


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  6 Responses to “How to Set Vista for your CPU L2 Cache memory”

  1. From my understanding this key only comes into play when Vista cannot / does not read the L2 cache level from HAL. Also, leaving it at 0 for some reason makes Vista default to a 256 K L2.

    Am I incorrect in this understanding?

  2. This dose not work at all. I have tied this and Default is still at 1024 on a AMD 64 X2 Dual Core 6000+ /2 1024 l2. Windows Vista would not let me or change it to 2048 or even lower it. I have Tired this in Vista 32 / X64 bit SP1 Versions. i think its more for Intel Processors

  3. This only applies to CPUs with an off chip cache, so unless you’re running Vista on a Pentium II [codename Tonga] or older, this will have no effect.
    That’s why Windows doesn’t do it by itself.

  4. This is a myth.

    The default value for this setting is 0, which tells Windows to auto-detect the correct value. Many settings in the registry work this way. The setting is only needed for ery old CPU’s, prior to the Pentium II. In no event will Windows set the detected value in the registry, it will remain at 0.

    Windows only uses this value to optimize some low level memory allocations. The performance penalty for getting it wrong is very low, usually less than 2%. Windows does not use the cache, it is used only by the processor which will always use the full size.

    Bottom line: Unless you are using a CPU more than 10 years old this setting will do nothing.

    Larry Miller
    Microsoft MCSA

  5. [...] a CPU more than 10 years old this setting will do nothing. Larry Miller Microsoft MCSA Source: How to Set Vista for your CPU L2 Cache memory | Windows Reference So I guess you can delete them from your initial post __________________ And the people shall [...]

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