Mozilla’s Firefox 141 introduced a range of on-device AI capabilities, including Smart Tab Grouping, automatic tab naming, and an optional AI chatbot in the sidebar. While these tools are designed to run locally for privacy and faster responses, some users have reported that they significantly increase CPU usage, trigger constant fan noise, and reduce battery life.
The issue centers on a background process called Inference, which is responsible for running Firefox’s AI models. In some cases, CPU usage spikes have exceeded 100% even during light browsing. Disabling AI features has been shown to reduce or eliminate these performance issues.
Why Firefox AI can cause performance issues
All AI features in Firefox — whether it’s grouping and naming tabs or powering the chatbot — rely on local AI processing. While this avoids sending your data to external servers, it also means your CPU is constantly working to process content in real time. This can be particularly demanding on laptops and lower-powered desktops.
User reports indicate that Smart Tab Grouping is the most resource-hungry feature, but other AI components can also contribute to the overall load. Turning off all AI functions offers the best chance of improving performance.
How to disable Firefox AI features
Follow these steps to disable them from advanced settings:
- In the Firefox address bar, type about:config and press Enter.
- Accept the warning message to proceed to advanced settings.
- Search for and set the following entries to false:
- browser.tabs.groups.smart.enabled (Smart Tab Grouping)
- browser.ml.chat.enabled (AI Chatbot)
- browser.tabs.groups.smart.enabled (Smart Tab Grouping)
- Restart Firefox to apply the changes.
Once these settings are disabled, the Inference process should no longer run continuously in the background.
Optional: Remove downloaded AI models
You can also remove any AI models that Firefox has stored locally:
- Go to the add-ons page by typing about:addons in the address bar.
- Look for any section related to “On-Device AI” and remove downloaded models if present.
- Restart the browser.
Firefox’s on-device AI approach is meant to deliver smart features without compromising privacy, but the trade-off is higher system resource usage. By disabling all AI-related features and removing any stored AI models, users can restore normal CPU performance, extend battery life, and keep their browsing experience smooth until Mozilla rolls out performance optimizations in future updates.
