XF 1.5 Identify which Add-on is causing server lag?

[OakleyForum]

So an interesting problem here, my forum is currently loading very slow (and has been for the last few months). Despite adding a CDN is has continued. Google PageSpeed's pegged it to slow server response time (3.2s), however running my own tests, it seems to only be on the front facing site. I.e When I go to OakleyForum.com, it takes ~3s just to get the first packet, then the rest is loaded quickly; however when I go into the AdminCP, or upload a test file outside the forum, the pages load blazingly fast.

Disabled all add-ons in library/config.php and it sped it up, but I'm struggling to figure out what specifically is causing it. I have made no changes to add-ons used in the last few months.

Are there any tools/methods to determine which specific add-ons/code are causing the slow first load.

Thanks!

 

[Optic]

If you enable debug mode this will add a total time loaded at the footer, then if you click that it will list all the database queries along with how long it takes to process each one.

I'd probably start there..

 

[Alpha1]

Indeed. Do this for every type of page. Eliminate all slow queries. Also check out @Xon 's slow query logger.
If you have waindigo addons then start disabling those.

 

[Xon]

I also have a number of performance related add-ons, that I really should bundle into a single release.

How many add-ons do you have installed and by which developers? It is very easy to negatively impact site performance if the developer wasn't careful.