Intro to Computer Systems

Chapter 12: System Integration

Price, Performance, Power

In any discipline, the choice of components and materials always involves compromises - very rarely is there one clearly superior product or substance that is appopriate for all use cases. In mechanical and building design, a common mantra is "Light, cheap, strong. Pick two!"

When it comes to selecting computer subsystems, it could be paraphrased as, "Price, performance, power consumption. Pick two!"

A "Balanced System"

Occasionally, the concept of a "balanced system" is bandied about - that a system of a certain processor performance (to take one yardstick) somehow requires a particular graphics card, memory capacity or mass storage system to achieve a sense of "balance".

This is a misnomer as a system is built not as a monument to itself, but to serve a need - and very few computing needs stress each subsystem an equal and balanced amount. Most often a computer that is "great at everything" is overpriced and expensive to run, compared to a properly optimised system.

To achieve the optimal balance of price, performance, power consumption (and perhaps also reliability) the ideal situation is to analyse and select each subsystem to serve its intended purpose, and forget the idea of "balance".

Taken to an extreme, an optimal system for a professional author may well be a $400 computer that's attached to a $2000 monitor and $300 keyboard of the highest quality and ergonomics.

Why might this be so? The task isn't particularly performance-sensitive; a system integrator might consider that the "bottleneck" to be the interface between the user and computer system.

Compromise with Components

Taking each of the eight subsystems identified earlier, the major compromises in selection are summarised below.

CPU

Memory

Motherboard and Chipset

Graphics and Display

Mass Storage

Expansion Options

Power Supply

Enclosure and Cooling