couple of other options you can try.
1. Make sure your network card drivers are up to date.
** This step makes changes directly to your registry **
2. Download SG TCP optimizer from
http://www.speedguide.net/downloads.php and set it to Optimal but can use default then make sure to reboot your computer.
Back when i use to do tech support i used tcp optimizer a ton to fix speed/connection issues on people computers and never had it cause any harmful effects personally.