Symptom(s):

Slow network performance under Windows Server 2008*.

Cause:

Windows Server 2008* uses TCP window scaling to maximize network performance. Older routers, firewalls, and operating systems not compatible with this feature might see slow data transfer or loss of connectivity.

If the issue only happens with Hyper-V, see Low network performance observed with Microsoft Windows 2008 R2*

Solution:

1. Make sure your router, firewall, and client operating system support TCP window scaling.
2. Check with the network device manufacturer for firmware updates that support TCP window scaling.
3. If the issue continues, disable TCP window scaling on Windows Server 2008* by running this command:
   netsh interface tcp set global autotuninglevel=disabled

Related topics:
See the following Microsoft knowledge base articles for more information:
http://support.microsoft.com/kb/929868
http://support.microsoft.com/kb/932170
http://support.microsoft.com/kb/935400

Operating System:

Windows Server 2008 *

This applies to:

Intel® Server Board S3200SH Intel® Server Board S5000PAL Intel® Server Board S5000PSL Intel® Server Board S5000VCL Intel® Server Board S5000VSA Intel® Server Board S5000XSL Intel® Server Board S5400SF Intel® Server Board S5500BC Intel® Server Board S5500HCV Intel® Server Board S5500HV Intel® Server Board S5500WB Intel® Server Board S5520HC Intel® Server Board S5520UR Intel® Server System SC5400RA Intel® Server System SR1530CL Intel® Server System SR1530HCL Intel® Server System SR1530HCLS Intel® Server System SR1530SH Intel® Server System SR1560SF Intel® Server System SR1600UR Intel® Server System SR1625UR Intel® Server System SR1630BC Intel® Server System SR1680MV Intel® Server System SR2520SA Intel® Server System SR2600UR Intel® Server System SR2625UR Intel® Workstation Board S5000XVN Intel® Workstation Board S5520SC