Basic Dot Net Question:

Server controls are a part of ASP.net. When a server control is used there will be an extra overhead on the server to create the control at run time and accordingly set the values. HTML controls are static controls and are easy to use. They are supported is ASP.net.
As a rule, if there is a corresponding HTML control available instead of the server control, you should always go for the HTML control as it enhances the server performance and ensures faster response. Server controls should be used when it is found that the available HTML controls are not sufficient to achieve the task.