I was recently troubleshooting a performance issue on one of the servers we manage and I came across a posting on Greg Galipeau’s Weblog that covered problems that a couple of network adapters have with TCP Chimney. TCP Chimney is a concept introduced with Service Pack 2 for Windows Server 2003 and is supposed to increase a server’s performance. However, two network adapters have a known issue with TCP Chimney:
- BroadCom NetXtreme II
- Hewlett-Packard NC373i Multifunction Gigabit Server Adapter
As it turned out, the server I was troubleshooting had the HP adapter installed so I followed Greg’s instructions, which are outlined below:
- Disable TCP Chimney from a command prompt by typing Netsh int ip set chimney DISABLED
- Make a few registry changes to make sure that performance is not hindered by disabling TCP Chimney. Click Start, click Run, type regedit in the textbox, and then click the OK button.
- Locate the following registry subkey: HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
- Double-click the EnableTCPChimney registry entry.
- In the Edit DWORD Value dialog box, type 0 in the Value data textbox and then click OK.
- Double-click the EnableRSS registry entry.
- In the Edit DWORD Value dialog box, type 0 in the Value data textbox and then click OK.
- Double-click the EnableTCPA registry entry.
- In the Edit DWORD Value dialog box, type 0 in the Value data textbox and then click OK.
- Restart the server.
For additional information regarding TCP Chimney issues, please review Microsoft Knowledge Base article 942861.
