A simulator is only useful if you can run it for hours without it fighting back. We built the replay engine around one rule: the UI must stay responsive even at top speed. Hover tooltips track, the order panel accepts input, the chart redraws cleanly — whether you're at 1× watching each bar form, or at 10× compressing weeks into an afternoon.
What that means in practice
Your browser stays under 5% CPU even at top speed, the fan doesn't spin up, and you can leave a session running in a background tab without it stealing your machine. Tested on a six-year-old laptop at 60fps from the first bar to the last.
Performance here isn't a vanity metric. A simulator that heats up the room is one you stop opening, and a practice tool you don't open trains nothing.
The speed is only worth having if the repetitions are honest — the case for compressed practice time covers what it buys you.