In case you host your sites on a dedicated hosting machine, you would expect that they shall perform very fast and that the access speed to them will depend exclusively on the Internet connection of the visitors. Having said that, this will not be the case if the server has poor network connectivity or relies on a network card, which simply cannot deal with high volume of website traffic. If this is the case, it shall take a while for your websites to load if lots of people open them simultaneously or visitors could see error messages. As a result you could lose visitors as probably many people won't revisit your site if they have experienced problems or slow loading speeds. That is why you ought to pay attention to the network components of any new hosting server that you purchase and not just to the main hardware like CPU, Ram memory or hard disk.