This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Hierdie gesprek is in die argief. Vra asseblief 'n nuwe vraag as jy hulp nodig het.

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

  • 6 antwoorde
  • 1 het hierdie probleem
  • 3 views
  • Laaste antwoord deur hforn

more options

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)

more options

Adding screenshot

more options

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.

more options

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.

more options

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.

more options

"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?

more options

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.