Bandwidth
is the amount of data that can be transmitted through a connection at a given moment to a server. The higher your bandwidth, the larger amount of traffic your site can handle at fixed amount of time.
Bandwidth is an amount, which can be transferred in a fixed amount of time. This term is also used to describe the rated throughput capacity of a given network medium or protocol. Bandwidth is measured in MB or KB per second. Usually web hosting companies set limitations on bandwidth you are allowed to use and its exceeding could cost you money. So be sure to know the amount of Bandwidth you are permitted to use.
What is the Amount of Data?
Data that is transferred as Bandwidth is usually measured in Bytes that is simply 8 bits. You should remember that in the world of computers measurements are represented by the power of two, as in the real world the same goes for the power of ten. This condition resulted in that Kilobyte means 1024 bytes and not 1000 as you might've expected. Also remember that Megabyte is 1024 Kilobytes and 1048576 bytes, the same calculation is used for Megabytes. So the amount of transferred bytes or bits per second is considered to be Bandwidth.
Every request made to your web site means some data has to be returned to the computer that has made it. The total amount of such data transfer is called your Bandwidth Usage. There are usually two types of Bandwidth usage such as "instantaneous" usage and the monthly usage. Theses types are made by the same principals the different is in the period of time they are measured.
The "instantaneous" usage type of bandwidth usage is important to network managers but not really to the end users.
Monthly bandwidth is the way the web hosting company accounts your bandwidth usage. The web hosting company is OK with you used your monthly bandwidth in one day as long as you do not exceed the specified amount of Bandwidth usage.
You should remember that as the amount of your bandwidth usage is a result of that how many visitors your web site has, the bigger your web site is the more bandwidth you are going to need. And the larger your files are the more bandwidth will be consumed per visitor.
Content Downloading Delay
As your website popularity directly depends on the amount of visitors who prefer visiting web sites which can download fast you should remember what is considered to be fast.
0.1 of a second is considered to be the limit for user to feel that the system is reacting instantaneously so no special feedbacks are necessary except to display the results.
1.0 second delay, in this case the user will notice the delay. Normally no special feedback is necessary during such delays though the user loses the sense of operating directly on the data.
10 seconds delay is the limit to keep the user's attention focused. Exceeding of this limit makes the user to switch to other tasks while waiting for computer downloading.
You should also consider that if your page constantly downloads taking the same period of time the user will know what to expect, which is positive aspect too.
Your web site content downloading just like required bandwidth directly depends on the site's quality. The bigger the image sizes in pixels (Frame size), the higher the Frame rate, the higher the picture quality and the number of colors the more bandwidth is going to be needed to play back the content. In this case you should consider which of these qualities are the most important for your web site and which ones you can sacrifice. And the more bandwidth you have the more freedom you have to include audio, video or some scripts and other data with minimum influence on your web site efficiency.