Speed on Internet

It depends on the speed (clock speed) of your computer and the level or amount of bandwidth you purchase from your cable service.

It depends on both, as well as a few other small factors, but generally it's the speed of your ISP which is the slowest link in the chain.

Speedtest.net and the TraceRoute command are your friends

What are Speedtest.net and the TraceRoute commands?

Speedtest.net is a site which will help you test your functional bandwidth across the Internet. It's a good way to confirm that your ISP is giving you the bandwidth they promise.

Traceroute is a command line tool which will display the route across various network segments that your target request takes. It also gives you some information about hop times. It's useful if you're having a failure somewhere between yourself and your target and are wondering where the packets are failing.