One specific large Trello board suddenly becomes extremely slow on Windows

[Oleksii]

Hello,

We are experiencing a recurring performance issue with one specific Trello board.

The board contains many cards, checklists, and attachments, so we understand that it is relatively heavy. However, its size has not changed significantly: it can work normally one day and become practically unusable the next. This has already happened several times over the past year, the issue appears, persists for some time, and then disappears without any changes on our side.

Current symptoms:

• The board takes a very long time to load, freezes, and responds slowly.
• Trello consumes up to approximately 7 GB of RAM.
• The issue affects multiple users, not just one account or computer.
• It occurs on Windows in both the web and desktop versions.
• Other Trello boards work normally on the same computers.
• The same problematic board appears to work normally on MacBooks.

We have already tried the standard troubleshooting steps: different browsers, incognito mode, clearing cache and site data, disabling extensions and Power-Ups, checking card covers, hardware acceleration, network connection, and the desktop application. None of these provided a stable solution.

Because the same board previously worked normally with approximately the same amount of data, we suspect a board-specific regression, client-side memory leak, or Windows/Chromium rendering issue rather than simply the number of cards.

Could the Trello/Atlassian team please investigate this board and check whether there are any abnormal API responses, problematic board data, rendering loops, or recent client-side changes affecting large boards on Windows?

We can provide the board URL/ID, browser console errors, HAR file, memory usage screenshots, affected account details, and reproduction steps privately.