Disabling Bus Mastering On 3Com 3C590 PCI Network Cards

• Microsoft Windows NT Workstation version 3.51 and 4.0
• Microsoft Windows NT Server version 3.51 and 4.0

SUMMARY

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.

NOTE: You may also disable bus mastering to avoid contention between two busmastering devices.

MORE INFORMATION

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, etc.)
   

6. Open Parameters folder

7. Choose 'Add Value' option in the Edit pull down menu

8. Type Busmaster for the value

9. Check that the data type is REG_SZ

10. Click the OK button

11. Type NO in the string box

12. Check the registry to verify that the following line was added

         "Busmaster:REG_SZ:NO"
    

13. Shutdown and restart NT

1. Open Event Viewer under System

2. Click on first instance of EI59X

3. Should read "Busmaster support has been turned off for slot XX"

   http://infodeli.3com.com/infodeli/swlib/shipping_adapter_files.htm

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.