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How can I debug slow page loads deeper than just developer tools(F12)

  • 6 replies
  • 1 has this problem
  • 3 views
  • Last reply by hforn

hforn
hforn
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Hi all, I'm debugging a frustrating issue where sometimes pages will load extremely slowly. I've attached a screenshot of the developer tools that will perhaps show my issue more clearly. Right after Firefox starts up, the first loading of a page takes forever to load. This doesn't happen on a blank tab/start screen. This happens for fresh installations as well - no plugins, no profiles, cache, etc. As you can see from the screenshot, it took 90 seconds to load reddit.com - with 90 seconds in "Blocked."

I'm not saying this is a Firefox issue - it's probably not, perhaps antivirus or malware, Windows updates, etc. But I'd like to know how to drill down on this problem.

Windows 10, 59.0.1-64 bit

Hi all, I'm debugging a frustrating issue where sometimes pages will load extremely slowly. I've attached a screenshot of the developer tools that will perhaps show my issue more clearly. Right after Firefox starts up, the first loading of a page takes forever to load. This doesn't happen on a blank tab/start screen. This happens for fresh installations as well - no plugins, no profiles, cache, etc. As you can see from the screenshot, it took 90 seconds to load reddit.com - with 90 seconds in "Blocked." I'm not saying this is a Firefox issue - it's probably not, perhaps antivirus or malware, Windows updates, etc. But I'd like to know how to drill down on this problem. Windows 10, 59.0.1-64 bit

All Replies (6)

hforn
hforn Question owner
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Adding screenshot

Shadow110
Shadow110
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Hi, will avoid your question till next time.

There appears to be an issue that only affects users who have turned off cleartype font rendering within their windows settings. So a workaround for the moment would either be to turn cleartype back on or disabling hardware acceleration in Firefox: https://support.mozilla.org/en-US/kb/performance-settings

Please let us know if it worked.

cor-el
cor-el
  • Moderator
  • Top 10 Contributor
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What security software do you have?

Boot the computer in Windows Safe mode with network support to see if that has effect in case security software is causing problems.

hforn
hforn Question owner
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I'm fairly certain it's Windows Defender, I'm not too interested in trying to fix the issue, I'm more interested in if there are debugging mechanisms built into Firefox instead of having to rely on black-box debugging utilities like Visual Studio or WinDbg.

jscher2000 - Support Volunteer
jscher2000 - Support Volunteer
  • Top 25 Contributor
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"Blocked" is supposed to mean Firefox already had the maximum number of connections open to that host, so it waited until one of them closed.

https://developer.mozilla.org/docs/Tools/Network_Monitor#Timings

Was Reddit also open in a different tab?

hforn
hforn Question owner
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jscher2000 said

"Blocked" is supposed to mean Firefox already had the maximum number of connections open to that host, so it waited until one of them closed. https://developer.mozilla.org/docs/Tools/Network_Monitor#Timings Was Reddit also open in a different tab?

Nope, fresh installation of Firefox, Reddit was the first and only page opened.