MS: HOW TO: Modify the Default SizReqBuf Value in Windows 2000

This article describes how to modify the size of the SizReqBuf value. In File and Printer Sharing for Microsoft Networks, the SizReqBuf value determines how much data is buffered at one time to send to a client. The default values in Windows 2000 provide acceptable levels of performance in typical scenarios. However, on a high-latency connection, you may want to use an increased SizReqBuf value.
http://support.microsoft.com/?kbid=320829