This has worked for a lot of people in Win XP... and supposedly a few people in Vista...
if you scroll past the Eng/Rougue QQ you'll get to it
http://roguerogue.com/2009/05/20/stealth-nerf-nitro-boots-death-engineering-fixed-ping/but it's worth reading fung's comment on the website
I've done some digging and what this does is it Disables Nagling.... Nagle's algorithm basically waits for a handful of very small packets before sending it through the net, much more efficient transfer.
when you set the TcpAckFrequency to 1 you DISABLE Nagling which means small packets can go without being clumped. That's why your ping can decrease.
It WILL affect other programs but perhaps not too badly
read more here
http://www.speedguide.net/read_articles.php?id=2574under the Gaming Tweak Section
