As shown, Constant Bandwidth provides explicit support for hard real-time execution (reserving a bandwidth to each hard task, or scheduling it directly with the EDF algorithm), but also Proportional Share can emulate it, at the cost of the additional overhead of dynamically rearranging the tasks' weights. Using EEVDF, a hard guarantee can be performed at the cost of guaranteeing a computation time Ci + Q.
On the other hand, Proportional Share schedulers are more flexible in partitioning the bandwidth among non-guaranteed tasks: this is useful to run non real-time applications (such as in a traditional workstation) together with multimedia ones. In this case, the notion of weight is more intuitive than the reserved bandwidth; Constant Bandwidth can emulate this, by defining Bi=Fi, Ti = Q / Bi and using non Real-Time (NRT) tasks (an NRT task is a task composed by a single, finite or infinite, job).