A memory capacity of 16 GB can be reached at computers and laptops generally have multiple modules. So four 4 GB DDR3 SDRAM modules for example. Combined or there are two 8 GB modules are used. For server systems and workstations that use ECC memory, but even 16 GB RAM modules are possible because the maximum total capacity is higher here mostly.
Performance Technically, 16GB of memory today for top performance class in client computers. Especially with workstations for complex applications such as CAD, simulation and virtual reality, is a high capacity is advantageous since the system can perform many calculations faster and more flexible use permits.
The server is always depends on the particular application. Often, however, are also here 16 GB RAM already sufficient for many different applications. Depending on the operating system occupied or planned server service, but more memory can be beneficial, especially if many users to have access.