Windows allots 20 per cent of the bandwidth by default for various services like Windows update and spyware checks. The trick is fairly simple to get hold of the unused bandwidth. Here's what you do Go to Start> Run and type gpedit.msc. Go to Administrative templates Networks > QoS Packet Scheduler. Click on Limit Reservable Bandwidth and check the enabled box and then change the Bandwidth limit from 20% to 0 %. The screen shots above are the before and after results.
To ensure that while browsing you get a fair amount of speed without disrupting your downloads, capping your bandwidth comes in handy. Developed to control and monitor internet traffic the Netlimiter application limits your bandwidth. So for example let's say you want to download a software and play CS at the same time, but do not want your game to lag. The download speed you get is, say, 4 Mbps; limit it in a 2:2 ratio so that your movie download continues while you play CS without any breaks. This is what you do when you start your download, go to Netlimiter you'll see DL speed on top which would show you your current download speeds let’s say for example you're getting 300kbps change this to 150. Once you have changed the value you can start enjoying your game while the download happens in the background.
SG TCP Optimizer
A free application to enhance your Internet speed, weighing a mere 419 KB the SG TCP optimizer takes into account only the necessary registry parameters and tweaks the overall speed making browsing lighter and faster than before. Just run the .exe file and follow the instructions.