If you host your websites on a dedicated server, you would expect that they shall perform lightning fast and that the access speed to them shall depend solely on the Internet connection of the site visitors. Nevertheless, this is not going to be the case in the event that the hosting machine has poor network connectivity or employs a network card, which just cannot deal with high volume of website traffic. If this is the case, it'll take a long time for your websites to load if lots of people open them at the same time or visitors could see error messages. Therefore you may lose website visitors as most probably many people won't revisit your internet site if they have experienced problems or slow loading speeds. That's why you should pay attention to the network components of any new hosting server which you purchase and not just to the main hardware which includes CPU, RAM or hard disk.
