A server is a standalone computer that is intended to be used as a resource storage and allocator within a communication framework. Servers exist in different forms depending on how they are assembled and operate.
A tower server is simply a computer that has been assembled in a cabinet with the standard CPU but its functionalities are to offer dedicated services in a busy environment. A single server may be sufficient to an organization needs, but in the case of big companies that demand huge disk space that can handle high-speed simultaneous processing that is where either a Tower or a 1u server is needed.
Tower servers are basically made in cabinets with stand-alone hardware components that are specifically been configured to perform defined tasks. This kind of server once installed are known for their small size, scalability and faster cooling. One big disadvantage we have here is the bulkiness and it takes up a lot of space not to mention the cabling technicalities one may need.
A Xeon server is smaller in build and can be stacked one upon the other in a server room with well-designed rack space. This means less server room space is needed to have multiple servers installed. You will need to invest in a cooling system that will maintain room Temperature for the Xeon servers to operate.
The physical and visible difference between the two servers is that a Tower is placed in a cabinet while a Xeon is mounted on racks.