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Firefox in safe mode is fast, outside safe mode with all extensions and acceleration disabled is slow

  • 4 replies
  • 1 has this problem
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  • Last reply by Photon44

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Ironically this seems to have started when I was showing off Firefox to co-workers who are Chrome users.

I've noticed Firefox become very slow especially in GMail. In Firefox's performance profiler it reveals that the majority of the slow times (ie. 1798 ms out of 2971 ms) is spent in JIT (see screenshot).

I tried disabling all extensions, updated my graphics driver to the latest version (Intel HD Graphics 4000 10.18.10.5059), and then disabled hardware acceleration. Nothing sped it up.

However, if I start Firefox in its safe mode it's fast with snappy responsiveness, even in GMail. I've run out of diagnosing ideas.

Ironically this seems to have started when I was showing off Firefox to co-workers who are Chrome users. I've noticed Firefox become very slow especially in GMail. In Firefox's performance profiler it reveals that the majority of the slow times (ie. 1798 ms out of 2971 ms) is spent in JIT (see screenshot). I tried disabling all extensions, updated my graphics driver to the latest version (Intel HD Graphics 4000 10.18.10.5059), and then disabled hardware acceleration. Nothing sped it up. However, if I start Firefox in its safe mode it's fast with snappy responsiveness, even in GMail. I've run out of diagnosing ideas.
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All Replies (4)

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If you are having issues with the performance of Firefox, you can try refreshing Firefox. Similar to Safe Mode, this will revert certain settings and remove any downloaded extensions, while preserving personal data (boomarks, passwords, etc).

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I refreshed now but there's no improvement.

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If you are using the 64-bit version of Firefox, try switching to the 32-bit version to see if that improves anything. If you are running the 32-bit version, try changing the to the 64-bit of Firefox (if your system is compatible).

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I'm running the 64-bit version so I installed 32-bit and it was just as slow. I uninstalled 32-bit and re-installed 64-bit and still no improvement.