Working with a slow internet connection is very discouraging. It is also time consuming. Here are some of major causes of slow internet connection.
Problem with the service internet provider
Often the problem is caused by the Internet serv
ice provider, who is sharing the Internet connection among several different customers. This makes sense because the customers are not usually all using the Internet at the same time. The Internet service provider has to buy Internet connections from the backbone providers, so it would be wasteful to have one for each customer who is not using it most of the day.
But when the peak hours hit the Internet, usually when people get home from work, you can notice a significant increase in the lag when you are trying to access websites, and this can be because multiple customers are using the same connection at the same time.
Glitches within the modem
Another frequent cause of the performance problems with Internet connections is glitches that can occur within the modem, and often this is the case when you’re using a cable modem or a DSL modem which is external to the computer. If you’re not sure what this is, this is probably the box that plugs into the cable from the wall, which then plugs into your computer.
From time to time, this can have technical problems just like a computer can, so you need to restart it by switching it off and back on again. You should probably also take the opportunity to reboot the computer as well, to ensure that you get good performance.
Computer infection
Also, when your computer is infected, it is 
very normal for it to be used to attack other computers, and spread malware infections, allowing the hackers to build up an army of computers which they control to cause chaos. This is known as a botnet, which means a network of robots.
It is also sometimes more colorfully described as a zombie network. What happens is your computer is now running under the command of the hacker, and it is using up your bandwidth to send attacks to other people. One real risk that you face with this is the possibility that the attack could be traced back to you, possibly causing legal problems and forcing you to prove your innocence.
Installed spyware
An even bigger risk is that there is possibly some spyware installed on your computer. Spyware is a type of software which is used to monitor your activities and steal vital information from you, such as your credit card details, your name and address, login details of various websites, and so on. This information can be used in identity fraud, and it can also be used to steal money from you.