I made this modification on an HP DL-360 with dual 1.3 GHz processors, 2GB of memory, and RAID 1 drive (two drives mirrored). It made a huge improvement accessing a directory with a lot of files. According to Microsoft (, ), the setting is increased in Windows 2003. I set in my NT 4.0 server to 16,644.

The SizReqBuf value is stored in the registry under the following registry key:
Value Name: SizReqBuf
Data Type : REG_DWORD
Data : 512 – 65535 (bytes in decimal, or 200 – FFFF hexadecimal)
Default : 4356 Specifies the size of request buffers that the server uses.

Source: http://support.microsoft.com/kb/320829