Title: Errors that won’t go away – Parallelize, Combine Javascript & Query Strings
Last modified: January 24, 2017

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# Errors that won’t go away – Parallelize, Combine Javascript & Query Strings

 *  [tekton23](https://wordpress.org/support/users/tekton23/)
 * (@tekton23)
 * [9 years, 4 months ago](https://wordpress.org/support/topic/errors-that-wont-go-away-parallelize-combine-javascript-query-strings/)
 * Hi,
 * I have the following results showing when I test my site on Pingdom:
 * F 0 Parallelize downloads across hostnames
    F 39 Combine external JavaScript 
   C 74 Remove query strings from static resources
 * I have looked and researched, but have no idea how to improve these within the
   settings of W3 Total Cache. Any advice or guidance would be much appreciated!
 * T23

Viewing 2 replies - 1 through 2 (of 2 total)

 *  [andreslucero](https://wordpress.org/support/users/andreslucero/)
 * (@andreslucero)
 * [9 years, 4 months ago](https://wordpress.org/support/topic/errors-that-wont-go-away-parallelize-combine-javascript-query-strings/#post-8692568)
 * To parallelize downloads across hostnames, you’ll need to set up multiple subdomains
   on your site or use a CDN such as KeyCDN, MaxCDN, Amazon Cloudfront, etc. Note
   that W3TC’s CDN option only supports a single hostname, but if you use a CDN 
   that serves files via HTTP/2 then the need to parallelize across hostnames is
   no longer an issue (because HTTP/2 parallelizes downloads by default).
 * To combine external JavaScript, enable the Minify option in W3TC. This will have
   the side effect of removing query strings from static resources that you’ve chosen
   to minify & combine.
 * If you want to remove query strings from other assets, uncheck “Prevent caching
   of objects after settings change”:
 * ![Screenshot](https://i0.wp.com/technumero.com/wp-content/uploads/2015/01/W3-
   Total-Cache-setting-Removing-Query-Strings-from-Static-Resources.png)
 *  Thread Starter [tekton23](https://wordpress.org/support/users/tekton23/)
 * (@tekton23)
 * [9 years, 4 months ago](https://wordpress.org/support/topic/errors-that-wont-go-away-parallelize-combine-javascript-query-strings/#post-8693746)
 * Thanks for your reply. I have a CDN installed and running. Both the CDN settings
   and Minify are already enabled in W3TC. Also the ‘Prevent caching of objects 
   after settings change’ was also already unchecked.
 * I have discovered that I do have a child theme installed. I wonder if this is
   causing those remaining issues, as I believe W3TC can only deal with one theme.

Viewing 2 replies - 1 through 2 (of 2 total)

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 * 2 replies
 * 2 participants
 * Last reply from: [tekton23](https://wordpress.org/support/users/tekton23/)
 * Last activity: [9 years, 4 months ago](https://wordpress.org/support/topic/errors-that-wont-go-away-parallelize-combine-javascript-query-strings/#post-8693746)
 * Status: not resolved