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JSI Tip 0301 - Performance tweaks for Windows NT 4.0.

It is possible that your Windows NT HAL (Hardware Abstraction Layer) does not recognize the amount of L2 cache (Secondary RAM Cache) that you have installed. To force Windows NT to recognize it, edit:

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

The value name SecondLevelDataCache is a type REG_DWORD. A data value of 0 is the default which causes the system to try to retrieve the size of the L2 cache from the HAL. If it is NOT successful, it uses 256K.

NOTE: This is only useful for computers with direct-mapped L2 caches. Pentium II and latter processes do not have direct-mapped L2 caches.

If you have a direct-mapped L2 cache which is not properly detected, set the value in decimal.

Example: If you have 512K cache, set the entry to 512 in decimal (Hexadecimal 200).

If you have lots on memory, set DisablePagingExecutive, a type REG_DWORD, to 1. This will allow drivers and the kernel code to be kept in memory. The default is 0 which pages drivers and kernel code when needed.

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