Registrations are now open. Join us today!
There is still a lot of work to do on the wiki yet! More information about editing can be found here.
Already have an account?

Microsoft KB Archive/141299

From BetaArchive Wiki
Knowledge Base

Disabling Bus Mastering 0n 3Com 3C590 PCI Network Cards

Article ID: 141299

Article Last Modified on 2/19/2007


  • Microsoft Windows 2000 Server
  • Microsoft Windows 2000 Advanced Server
  • Microsoft Windows 2000 Professional Edition
  • Microsoft Windows NT Workstation 3.51
  • Microsoft Windows NT Workstation 4.0 Developer Edition
  • Microsoft Windows NT Server 3.51
  • Microsoft Windows NT Server 4.0 Standard Edition

This article was previously published under Q141299

IMPORTANT: This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore it if a problem occurs. For information on how to do this, view the "Restoring the Registry" online Help topic in Regedit.exe or the "Restoring a Registry Key" online Help topic in Regedt32.exe.


As a test procedure or if you are experiencing bus contention with your 3Com 3C590 PCI or 3c595 (10/100 mb/sec) network cards, you can disable bus mastering to alleviate busmaster contention, or to test whether busmaster contention is the cause of your problems. This procedure can also be used with other PCI bus Network Interface Cards but you may not receive the listed notification in event viewer.


WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys And Values" online Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" online Help topics in Regedt32.exe. Note that you should back up the registry before you edit it.

To disable bus mastering:

  1. Run REGEDT32.
  2. Under HKEY_LOCAL_MACHINE open the System folder.
  3. Open CurrentControlSet folder.
  4. Open Services Folder.
  5. Open EL59X1 folder. (If you have more than one adapter, you need to repeat steps 7-15. The folders are named EI59X2, EI59X3, and so on.)
  6. Open Parameters folder.

NOTE: If the Parameters folder does not exist, it may be created from the Edit menu. To create the key, click the driver folder (EL59X1 folder), and then click "Add Key..." on the Edit menu. Name the key "Parameters", leave the class field blank, and then click OK.

  1. Select the Add Value option in the Edit pull down menu.
  2. Type Busmaster for the value.
  3. Check that the data type is REG_SZ.
  4. Click the OK button.
  5. Type NO in the string box.
  6. Check the registry to verify that the following line was added:


  1. Shut down and restart Windows NT.

To verify:

  1. Open Event Viewer under System.
  2. Click on first instance of EI59X.
  3. It should read "Busmaster support has been turned off for slot XX."

3Com suggests that you download the new Windows NT driver from its Internet site. The driver is available at:

The driver name is 3C59XN.EXE.

The 3C590 is manufactured by 3Com, a vendor independent of Microsoft; we make no warranty, implied or otherwise, regarding this product's performance or reliability.

Additional query words: lock hang freeze hangs freezes locks up 3C95X 3C950 3C905

Keywords: kbenv kbhowto kbnetwork KB141299