Need help with slow loading slider in Firefox & Safari

I have a couple of sliders on my homepage that are loading lightning fast in Chrome on Windows, but takes about 10secs to load in Firefox as well as Safari on a Mac.

We tried analying the waterfall data in browser console to determine what may be causing the sluggishness in only these browsers, but haven’t found anything conclusive.

We’ve also checked with the Query Monitor plugin, but it reports as is well with no issues.

The site is running through CloudFlare with SG Optimizer plugin for cache. We’d tried flushing that as well with no change.

  • Bamboo Kit
    • Staff

    Hello, Qureshi

    I hope you’re well today and thank you for reaching out to us.

    I've been inspecting through your site with Safari and Firefox on Macintosh and found the issue as you were mentioned, however, Safari and Firefox console shown many errors which can be the reason that may cause slider to load slow.

    This is a screenshot in Safari console.

    This is a screenshot in Firefox console.

    So I've investigated further more in your plugins, then found out that the problem might be with the plugin features in SG Optimizer. I would suggest you to disable "Load Render-blocking JavaScript Files Asynchronously" option in the SG Optimizer because this option can create some conflicts between the slider as it shown in safari console errors "ReferenceError: Can't find variable: videojs"

    This is a screenshot where you can find "Load Render-blocking JavaScript Files Asynchronously" option in SG Optimizer.

    Hope this helps, thank you.

    Kind regards,


    • Qureshi
      • Flash Drive

      Hi Bamboo Kit

      Thank you so much for the investigations. I have acted on your advice and disabled the “Load Render-blocking JavaScript Files Asynchronously” option in SG Optimizer.

      After that, I also cleared the cache in SG Optimizer and in CloudFlare too. But nothing happened; the issue persists!

      Please advice! :slight_smile:

      Best regards,


  • Bamboo Kit
    • Staff

    Hello, Qureshi

    I hope you’re well today and thank you for the reply.

    In this case, it’s hard to guess which plugins are causing this issue, however, I would advise you to perform a conflict test, including a theme change to a default theme or creating a staging site, please follow these steps below.

    First, create a recent backup in case you lose any settings during the test and have to restore to a previous working state.

    Then deactivate all plugins, activate a default theme like TwentySeventeen, clear all caches and check again if the issue is still there. If not, it means that something is conflicting, so start activating the remaining plugins and theme, one by one this time, checking every time for the reported issue, until you reproduce the issue, thus finding the conflicted combination.

    The following flowchart image can assist you during this test:

    If this is a live website with traffic, I’d rather advise to create a staging environment, meaning a complete and exact copy of this installation into another location/folder in the same server, using a separate database, and perform the test in there instead without worrying about the live site. Reference:

    Hope this help :slight_smile:

    Kind regards,


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