Fast Software, the Best Software: Why Speed is a Proxy for Engineering Quality

Speed as a Proxy for Engineering Quality

Software speed is one of the most valuable yet least valued assets in product development. When software is fast—meaning there is minimal to no lag between a user's intent and the application's response—it integrates smoothly into a user's life rather than becoming a hurdle. Speed often serves as a proxy for general engineering quality; when an application slows down during simple tasks, it suggests a lack of attention to detail that may indicate deeper, unseen architectural rot.

The Relationship Between Speed and Trust

Performance issues in simple operations can erode user trust in a tool's reliability. For example, if a text editor struggles to render a 5,000-word document, a user may begin to question the integrity of the application's sync capabilities or its ability to prevent data loss. Conversely, software that remains fast regardless of the scale of the input—such as Sublime Text, which maintains performance even with 50,000-line files—builds long-term confidence in its engineering foundation.

The "Meld" and User Flow

Great tools are defined by their ability to maintain a user's "flow"—the state of deep immersion in a task. Fast software allows a user to "meld" with the toolset, reducing the cognitive load required to operate the interface. This is compared to the directness of a physical typewriter, where every mechanical action happens as quickly as the user can move. When software introduces latency, it breaks this flow, transforming a creative process into a struggle against the tool.

Case Studies in Software Performance

High-Performance Tools

• nvALT: A plain text database that opens instantly and provides immediate search results, serving as an efficient "off-board brain."
• Figma: Despite being browser-based, Figma is noted for its extreme speed and intuitiveness, which the author attributes to "close-to-the-metal craft."
• Things: An iOS app praised for its tactility and purposeful animations that make the interface feel fast and fun to use.
• Keynote: A macOS application that balances power with a simple, responsive interface.

Performance Degradation and "Bloat"

• Adobe Photoshop and Lightroom: Once fast and sparky, these tools have become "gangly blobs" over time. The author notes that simple actions, such as opening a new file dialog in Photoshop, can take several seconds, leading users to migrate to faster alternatives like Affinity Photo.
• Google Maps: The transition from a focused tool to a complex application laden with slow animations and multi-UI variants has led to a perceived decline in usability, pushing some users back toward Apple Maps for its responsiveness.
• iTunes: Cited as the "nadir of software clunkery," its eventual decomposition into separate applications was a necessary response to its own bloat.

Speed Beyond Execution Cycles

Speed is not limited to CPU cycles; it also manifests as "work per user cycle." This includes the rationality of tool design and the clarity of language.

• Interface Rationality: A tool that operates logically (e.g., Figma's pen tool) reduces the time it takes for a user to achieve their goal.
• Linguistic Speed: Ambiguous or counter-intuitive language in UI dialogs (such as changing "Don't Save" to "Delete" in macOS unsaved file dialogs) can cause a user to second-guess their actions, effectively slowing them down.
• Tactile Responsiveness: In touch interfaces, speed is experienced as tactility. The iPadOS "Slide Over" feature is highlighted as superior to screen-splitting because it moves in synchronicity with the user's finger without the perceived lag of redrawing the screen.

Conclusion: The Goal of Lightness

Ultimately, the goal of software should be to become more elegant and "unbloat" over time. To be fast is to be light, and to be light is to lessen the burden on the user. When software is designed with a commitment to craft and speed, it enables fluency in creation rather than a battle with the interface.