You might not know that your Windows PC Internet speed is reduced by 20% by default. This 20% bandwith is reserved by Microsoft to upgrade their software. So you are deprived of this 20% more speed. So let's gain this 20% speed again.

(1) Start Menu> Run. Now type "gpedit.msc" and press "Enter"

(2) Now Local Group Policy Editor will open. Do the rest like this:
Local Computer Policy > Computer Configuration > Administrative Templates > Network > QoS Packet Scheduler

(3) Double click on "Limit Reservable Bandwidth". A new window will open. You will see "Not Configured" is selected.

(4) Select "Enabled". Now set Bandwith Limit 0%
and press OK

P.S: Just like the Home version of XP, the Group Policy Editor (gpedit.msc) is
not available in Vista Home Basic/Premium.