What is bandwidth
In its most basic definition, bandwidth describes the level of traffic and data allowed to travel and transfer between your site, users, and the Internet. Each web hosting company will offer a particular level of bandwidth. This is often a good indication of which hosting companies have the best of three essential components: Networks, connections and systems.
Usually, the more bandwidth a web host can provide, the faster and the better these three factors will be. At the same time, you should try to avoid attractive-looking “unlimited bandwidth” offers, as these are often not what they seem (more on this point later). “Unmetered bandwidth” should be more along the lines of what you are looking for.
Bandwidth and the Relationship With Web Traffic
Let’s use another analogy to help make bandwidth clearer. In this example, the bandwidth is the number of tables in a restaurant, and the web traffic is the diners. The math is simple: The more tables in the restaurant, the more patrons can dine there at any one time.
So generally it does impact on your page performance, and especially the load time of your website, in my opinion.
Also separating your mail server from your web server may be a good decision when you get into situation of receiving 70000 spam mails in the frames of 1 hour, because spam mails are quite common.