JSI Tip 9200. How should I tune the System Cache in Windows XP?

The System Cache (LargeSystemCache), which is enabled by default in Windows Server 2003, and disabled by default in Windows XP, controls the allocation of memory between programs and file sharing. The System Cache is designed to improve server performance by allowing information to be read from memory instead of re-reading it from disk.

NOTE: If you are using a server product as your desktop, you should disable the LargeSystemCache feature.

If you are using Windows XP primarily as a  server, you may want to enable the LargeSystemCache feature.

NOTE: If your computer uses an AGP (Accelerated Graphics Port) video or UMA (Unified Memory Architecture) video, you may experience random and severe performance decreases, as the drivers for these hardware components consume a large portion of available memory when the are initialized. This may cause insufficient RAM when other processes request resources, specially when transferring large files.

LargeSystemCache, a REG-DWORD data type, at HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSession ManagerMemory Management, can have the following settings:

1 = (Enabled) Maximize Throughput for File Sharing, which uses program memory for I/O functions when the cache is full.                        0 = (Disabled) Maximize Throughput for Network Applications, which uses cache memory only for I/O functions.

Additionally, the Server service uses Size, a REG-DWORD data type, at HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServiceslanmanserverparameters, which can have the following settings:

1 = Minimize Memory Used.2 = Balance.3 = Maximize Throughput for File Sharing and Maximize Throughput for Network Applications.

To configure the System Cache using the GUI:

1. Open Control Panel.

2. Open the System applet.

3. Select the Advanced tab.

4. Pressing the Settings button in the Performance area.

5. Select the Advanced tab.

6. Choose from:

         Programs       - If you are using Windows XP as a workstation.         System Chache  - If you are using Windows XP primarily as a server.

7. Press Apply and OK.

8. Shutdown and restart Windows XP.

To configure the System Cache using the registry, use Regedit.exe or REG.EXE. See More on Server Service tuning.

To configure the System Cache using a script, run TuneXPRAM Size LargeSystemCache:

TuneXPRAM.bat contains:

@echo offsetlocalif {%2}=={} goto syntaxfor /f "Tokens=*" %%a in ('@echo %1^|findstr "1 2 3"') do goto SizeOK:syntax@echo Syntax: TuneXPRAM Size LargeSystemCache (Size: 1 2 3, LargeSystemCache: 0 1)endlocalgoto :EOF:SizeOKset Size=%1for /f "Tokens=*" %%a in ('@echo %2^|findstr "0 1"') do goto LSCOKgoto syntax:LSCOKset LSC=%2@echo reg add "HKLMSYSTEMCurrentControlSetServiceslanmanserverparameters" /V Size /T REG_DWORD /F /D %Size%reg add "HKLMSYSTEMCurrentControlSetServiceslanmanserverparameters" /V Size /T REG_DWORD /F /D %Size%@echo.@echo reg add "HKLMSYSTEMCurrentControlSetControlSession ManagerMemory Management" /V LargeSystemCache /T REG_DWORD /F /D %LSC%reg add "HKLMSYSTEMCurrentControlSetControlSession ManagerMemory Management" /V LargeSystemCache /T REG_DWORD /F /D %LSC%@echo.endlocal