What is performance?

Performance is how well something works, especially how fast and efficiently it does its job. In tech, it usually means how quickly a computer, app, website, or device can complete tasks and how much resources (like memory, CPU, or battery) it uses while doing so.

Let's break it down

  • Speed: How fast a program responds or finishes a task (e.g., loading a page in 2 seconds).
  • Responsiveness: How quickly it reacts to user actions (e.g., clicking a button and seeing an instant result).
  • Resource usage: How much memory, CPU, disk, or network bandwidth it consumes.
  • Scalability: How well it keeps performing when more users or data are added.
  • Stability: How consistently it maintains performance over time without crashes or slowdowns.

Why does it matter?

Good performance makes users happy because they can get what they need quickly and without frustration. It also saves money: efficient code uses less server power, reduces cloud costs, and extends battery life on mobile devices. Poor performance can lead to lost customers, higher operational expenses, and a bad reputation for the product or brand.

Where is it used?

  • Websites and web apps (page load times, API response speed)
  • Mobile apps (smooth scrolling, quick startup)
  • Desktop software (fast file processing, low lag)
  • Games (high frame rates, low latency)
  • Servers and cloud services (handling many requests, quick data retrieval)
  • Embedded systems (real‑time control in cars, IoT devices)

Good things about it

  • Improves user satisfaction and retention.
  • Reduces hardware and cloud costs by using fewer resources.
  • Enables handling more users or data without adding extra infrastructure.
  • Enhances battery life on portable devices.
  • Gives a competitive edge; faster products often win in the market.

Not-so-good things

  • Optimizing performance can be time‑consuming and may delay feature development.
  • Over‑optimizing can make code harder to read, maintain, or extend.
  • Focusing only on speed might sacrifice security, accessibility, or correctness.
  • Measuring performance accurately requires tools and expertise, which adds overhead.
  • Some performance improvements need more expensive hardware, increasing upfront costs.