How to Speed Up a Slow Firefox Browser

By Site Editor · Updated September 10, 2026 · 9 min read

Firefox getting sluggish? A handful of targeted fixes — from trimming extensions to refreshing the browser — can bring it back to full speed without losing your data.

1. Disable extensions first

Extensions are the leading cause of Firefox slowdowns. Open the Add-ons Manager with Ctrl + Shift + A, switch every extension off, then restart Firefox and test speed. Turn them back on one at a time until you find the culprit.

2. Clear cache and cookies

Press Ctrl + Shift + Delete, set the time range to Everything, tick Cached Web Content, and click OK. If pages still misbehave, also clear Cookies and Site Data.

3. Adjust memory and hardware acceleration

Go to Settings → General → Performance. Uncheck Use recommended performance settings to reveal the hardware acceleration toggle. If Firefox stutters on video or graphics-heavy pages, try turning it off and relaunching.

4. Refresh Firefox

The Refresh button resets Firefox to its defaults while keeping bookmarks, history and passwords. Type about:support in the address bar and click Refresh Firefox in the top-right corner. This fixes deep configuration problems that individual settings cannot reach.

5. Keep Firefox updated

Open the menu → Help → About Firefox. Firefox checks for updates automatically on that screen. Installing the latest version often resolves performance regressions introduced in older builds.

Frequently asked questions

Will refreshing Firefox delete my bookmarks?

No. A Firefox refresh keeps bookmarks, browsing history, saved passwords and open tabs. It removes extensions, themes and modified preferences.

How much RAM should Firefox use?

A few hundred megabytes is normal for light browsing. If Firefox regularly exceeds 1–2 GB with only a few tabs open, extensions or a memory leak are likely responsible.

Does Firefox use less memory than Chrome?

It depends on usage, but Firefox generally uses somewhat less RAM by default. Both browsers benefit from fewer open tabs and fewer extensions.