said by nickfie:Microsoft has not yet published this. Their internal documentation was incomplete yesterday. They did not object when I proposed sharing on this forum. In fact, last night my support engineer was eager to go home and try this on his home PC - must be a member of the "I hate to wait" club
Microsoft Support provided the RegEdit in response to a support case I opened when my packet captures showed that IE7 & IE8 are throttled to 256 KByte windowsize in Vista & Windows 7. This limit holds regardless of how you configure autotuning.
The limit applies only to HTTP, so FTP and other protocols get full autotuning benefit. DrTCP doesn't show the problem because it opens its own socket.
This means IE on Vista or Windows 7 without the RegEdit is outperformed by:
- IE on tuned XP with TCP windowsize at 512 KByte or larger. My employer uses 1 MByte for better global performance.
- Any browser on Macintosh OS X Leopard or Snow Leopard. That's when Apple saw the light - big time - about TCP tuning.
- Google Chrome on Vista or Windows 7. Google apparently saw the problem and found a solution late 2008 / early 2009.
This RegEdit changes the default performance so IE on Windows 7 is competitive. Now my employer can consider upgrading from XP without making the business work slower.
My Linux box does provided largely window size buffer support also for better global performance that been there for all years as it was been provided for, However, I set it for both minimum is 64KB and maximum is 512MB buffer that is optional for the future of generation of physical network hardware upgrades. Microsoft have learned the lessons from Linux threat 
