Question

Give 5 reasons why usable capacity is smaller than nominal capacity.

(Performance analysis modelling class)

Answer 1

Solution)

• Nominal capacity: It is the maximum achievable under ideal conditions

-networks: nominal capacity = bandwidth
E.g., bandwidth in bits per second. The response time at maximum throughput is too high.

• Usable capacity: Maximum throughput achievable without exceeding a pre-specified response-time limit.

Usable capacity is smaller than Nominal capacity because of the following reasons:

1. Usable capacity when too low resources are overused.
2. Low throughput during ideal conditions where as Nominal is maximum achievable throughput under ideal conditions.
3. Utilization is less compared to Nominal.
4. Efficiency of Usable capacity is less.
   Efficiency: usable capacity / nominal capacity
5. The response time at maximum throughput is low
   whereas nominal capacity response time at maximum throughput is too high.