There is an unregistered 'free' version of NetBalancer, you're limited to controlling the bandwidth of no more than 3 applications. And so you could also use NetBalancer to identify malware, perhaps, by spotting its efforts to phone home. The program doubles as a useful bandwidth monitor, too, listing all your running processes, graphing current network activity, and detailing exactly which network connections an internet program has open at the moment. Or, in emergencies, you can prevent an application from accessing the internet at all. The program lets you assign download and upload priorities to your web applications, so you could, say, set your download manager to 'low priority' for a while, and your browser would automatically get a better share of available bandwidth. Install NetBalancer, though, and you'll be prepared for these situations. Until you decide you'd like to use your browser, of course, and find it's crawling along because there are only scraps of bandwidth left. Download managers are a great way to grab the files you need at the maximum possible speed.

Netbalancer free version