If you host your websites on a dedicated hosting machine, you would expect that they'll perform very fast and that the access speed to them shall depend exclusively on the Internet connection of the website visitors. Having said that, this won't be the case in case the hosting machine has lousy network connectivity or uses a network card, which simply can't deal with high volume of traffic. If this is the case, it will take a while for your sites to load if many people open them concurrently or visitors could see error messages. Consequently you may lose site visitors as probably many people won't revisit your website in case they have experienced difficulties or slow loading speeds. That is why you need to pay attention to the network components of any new hosting machine you buy and not just to the main hardware like CPU, RAM or hard disk.