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Low-end device test notes

The matrix first, the results when there is hardware

Performance notes usually arrive as a claim — “fast on low-end devices” — with nothing behind it. The part that can be published honestly today is the matrix: which classes, what hardware and network they represent, and what would be measured on each. Results need devices this build does not have, and the page says so rather than inventing a table of green ticks.

The matrix

Three classes, chosen because they fail differently. Publishing the matrix before the results is deliberate: it is the part that is checkable today, and it makes the missing results obvious.

Low-end phone

Hardware
4× slower CPU than a 2023 mid-range phone, 4 GB RAM
Network
Slow 4G, 400 ms RTT, 1.6 Mbps
Measured
First paint, longest main-thread task, dropped frames while scrolling the catalog with demos mounting.
Why this class
This is the class the blur budget and lazy mounting exist for: 289 mounting demos is a different problem at 4× slower.

Mid-range laptop

Hardware
2020 ultrabook, integrated graphics, 16 GB RAM
Network
Broadband, 40 ms RTT
Measured
Time to interactive on /components and /studio, layout shift while fonts swap, memory after five minutes on /lab.
Why this class
The default development machine is faster than this. Testing here catches the assumptions a fast laptop hides.

Reduced-motion, keyboard-only

Hardware
Any device, prefers-reduced-motion: reduce, no pointer
Network
n/a
Measured
That no animation plays, that the catalog is fully reachable by keyboard, and that focus is never trapped in a demo.
Why this class
Not a performance class in the usual sense, but the one where animation-heavy pages fail hardest.

No results are published, because none have been run

A device lab needs real hardware or a throttling service, and this build has neither. What it does have is a set of measurements that do not need a device: page weight from the compiled output, deferral counts from the HTML, blur sites and timer registrations from the source. Those are on the other pages of this section and each one names its source. Anything that would require a phone in someone's hand is listed above as a method, not as a result.