Atlassian teams continually monitor performance, looking at the time it takes to load the board for the first time and subsequent times.

• First time: We call this "Initial Load", and it includes resources for all the views plus assets like images, so it is usually longer.
• Subsequent times: We call this "Transitions", such as loading a board a 2nd time through clicking on the project side navigation after transitioning from the backlog (e.g. board -> backlog -> board), which is faster because most assets are already loaded.

To improve performance for boards with 300-500 cards, we are aiming for several milestones as part of a longer journey:

Today:

• Initial Loads: 90% of board loads within 12s, and 99% within 34s

• Transitions: 90% of board loads within 6s, and 99% within 13s

Milestone 1:  Achieved as of July 2021

• Initial Loads: 90% of board loads within 10s  (currently 7.6s), and 99% within 27s  (currently 25s)

• Transitions: 90% of board loads within 4s  (currently 4s), and 99% within 11s  (currently 10.7s)

Milestone 2:

• Initial Loads: 90% of board loads within 7s, and 99% within 14s

• Transitions: 90% of board loads within 2s, and 99% within 7s

Milestone 3:

• Initial Loads: 90% of board loads within 4s, and 99% within 10s

• Transitions: 90% of board loads within 1s, and 99% within 3s

We’ll update this issue with progress towards these milestones, and will do it at least every quarter. We have a public commitment to improve the performance of all key experiences within Jira (e.g. issues, search, filters, boards, and backlogs) as shown in our public roadmap.

What about boards with more than 500 cards?

We do not recommend having >500 cards on your boards. The board should ideally represent the highest priority for your team in the coming few weeks, and not contain all the issues in the project. This community post explains how to optimize your board to show < 500 cards.