Mozilla’s attempt to give Firefox a smart AI upgrade is backfiring, with users accusing the browser of becoming bloated and power-hungry.
The trouble began with Firefox version 141, which rolled out in late July 2025. The headline addition was AI-powered tab grouping, a local, on-device artificial intelligence feature that automatically sorts open tabs by topic and assigns them descriptive group names.
In theory, the feature improves productivity while keeping user data private, since the AI model runs entirely on your computer instead of the cloud. In practice, however, it’s being blamed for spiking CPU usage, draining laptop batteries, and even overheating systems.
The “Inference” Process Problem
Reports from Reddit, Mozilla’s support forums, and tech sites show a common pattern: a background process labeled “Inference” that’s part of the new AI system is constantly running, analyzing open tabs in real time.
On some machines, especially laptops and mid-range PCs, this process pushes CPU usage high, forces fans to spin at full speed, and cuts battery life dramatically.
One exasperated user on Reddit wrote: “I don’t want this garbage bloating my browser, blowing up my CPU, and killing my battery life.”
Tech publications have confirmed the performance complaints, with additional reports of chip power spikes and thermal throttling.
The criticism has led many longtime Firefox fans to accuse Mozilla of straying from the browser’s core strengths.
Why AI Makes Firefox Heavier
Running AI on-device means greater privacy, but it also demands constant processing power. Unlike traditional browser features, the tab grouping AI is always active in the background, scanning content to detect related tabs.
While newer, high-performance systems may handle the load without much impact, older or battery-powered devices feel the hit almost immediately.
How to Turn It Off
If you’ve noticed Firefox slowing down or running hot since updating to version 141, you can try:
- Disabling AI Tab Grouping
- Go to Settings > Tabs and toggle the feature off (availability may vary by build).
- Checking Resource Usage
- Enter about:processes in the address bar to see if “Inference” is consuming resources.
- Updating Regularly
- Mozilla may push performance fixes or provide opt-out options in upcoming releases.
As of Firefox 141.0.3, Mozilla hasn’t publicly addressed the CPU and battery drain complaints. With criticism growing louder, the company may be forced to tweak or roll back aspects of the feature to win back frustrated users.
