It is a good idea to do a speedtest and some pings to make sure your ISP is providing what you are supposed to be getting and to make sure your computer is working efficiently.
speakeasy.net/speedtest  will give you an idea about how much bandwidth you are getting


and to ping different places like google.com and yahoo.com you can type cmd in the search bar. then right click to run as administrator and  C:\Windows\system32>ping yahoo.com

Ofcourse it is good to sometimes reboot your modem and router.

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Thanks Wesley

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some other good testing sites, http://www.bandwidthplace.com/ and http://www.dslreports.com/.