In case you host your websites on a dedicated hosting machine, you would expect that they will perform extremely fast and that the access speed to them shall depend exclusively on the Internet connection of the site visitors. Having said that, this won't be the case in case the hosting machine has poor network connectivity or employs a network card, which just cannot cope with high volume of traffic. If this is the situation, it'll take quite a long time for your websites to load if lots of people open them concurrently or visitors may see error messages. Because of that you might lose visitors as almost certainly many people will not return to your site in case they have experienced issues or slow loading speeds. This is why you must pay attention to the network components of any new server you buy and not only to the main hardware such as CPU, RAM or hard drive.