Enabling NetDMA

Applies To: Windows Server 2008 R2

NETDMA provides services for offloading the memory copy operation performed by the networking subsystem, when receiving network packets, to a dedicated DMA engine.


NetDMA must be enabled in the BIOS before performing this procedure. NetDMA support is often labeled IOAT support. See the computer manufacturer’s documentation for information about modifying BIOS settings.


Incorrectly editing the registry might severely damage your system. Before making changes to the registry, you should back up any valued data on the computer.

To enable or disable NetDMA

  1. To open Registry Editor, click Start, click Run, type regedit, and then click OK.

  2. Locate the registry sub-key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters and click it.

  3. Locate the EnableTCPA registry entry. If this registry entry does not exist, right-click the Parameters sub-key, point to New, and then click DWORD (32-bit) Value).

  4. Replace New Value #1 by typing EnableTCPA, and then press ENTER.

  5. Double-click the EnableTCPA registry value you just created and do one of the following:

    • To enable NetDMA, type 1 in Value data, and then click OK.

    • To disable NetDMA, type 0 in Value data, and then click OK.