It looks like KB
948496 is getting pushed out as a
High Priority, Non-Security update through WSUS and Windows Update.
This brings Windows 2003 SP2 in line with the defaults in Windows 2008, which disables TCP offloading.
Update: I previously stated that Receive-Side Scaling was also disabled by default in Windows 2008 - I was wrong! Thanks to those who pointed out this error!
If you are curious what your current settings are in Vista or Windows 2008, you can simple run
netsh int tcp show global .
The results will look something like this (some options may be different than mine):
Receive-Side Scaling State: enabled
Chimney Offload State: enabled
Receive Window Auto-Tuning Level: normal
Add-On Congestion Control Provider: ctcp
ECN Capability: disabled
RFC 1323 Timestamps: enabled
I have RSS enabled, Offload enabled, and CTCP turned on due to my system's specific configuration and broadband connections. CTCP helps out 3G networks. Ditto for Timestamps (usually).