Cannot enable I/OAT with 82576 on Windows Server 2008 R2

[GBonn1]

I have a motherboard (Supermicro) with Intel 5520 Chipset+ICH10 with dual socket configuration populated with 2 Xeon 5670. The motherboard design has the Intel 82576 network chip. I installed Windows 2008 R2 and proceeded to install the network driver using the latest driver available on Intel site. When I use the IOATCHK utility provided on the Network Connection CD the utility complains that the hardware doesn't support I/OAT. Yet my understanding is that it should.

What wrong?

[Daniel_O_Intel]

From http://downloadmirror.intel.com/12193/eng/readme.txt

Intel I/OAT requires the following to operate on Microsoft Windows Operating Systems: - A server chipset and BIOS that are Intel I/OAT capable - An adapter or network connection that is Intel I/OAT-capable - The RSS advanced setting must be enabled - Under TCP/IP Offloading Options, both Offload Receive IP Checksum and Offload Receive TCP Checksum must be enabled.

I'd double-check the BIOS on the board, make sure it's enabled, and make sure you've altered the two NIC settings.

[GBonn1]

I had already checked this list before asking. But I did double check again to make sure I didn't forget anything. I meet all these requirement. The BIOS does have the IOAT setting to enable.

Yet the IOATCHK utility does say that the hardware doesn't support IOAT.

However using the command:

netsh int tcp show global

I got this report :

C:\Users\Administrator>netsh int tcp show global

Querying active state...

TCP Global Parameters

----------------------------------------------Receive-Side Scaling State : enabledChimney Offload State : automaticNetDMA State : enabledDirect Cache Acess (DCA) : disabledReceive Window Auto-Tuning Level : normalAdd-On Congestion Control Provider : ctcpECN Capability : disabledRFC 1323 Timestamps : disabled

The DCA is disabled but the BIOS has the DCA set to enable. Could this be the problem ?

Here there another means beside IOATCHK to check if IOAT is enables?