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Slow load time - using Optimizely WP Plugin

jaredcodling 05-05-16
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Slow load time - using Optimizely WP Plugin

Hey guys,


Has anyone experienced severely slow load time?


Have never used Optimizely before, but it has basically doubled our load time, and halved our conversion rate - it's so bad we had to switch it off.


We're just using 'redirect split' too, we're not even modifying the page!


Anyone have a fix? Code is in correctly from what I can tell, and it should be as we're using the Optimizely plugin.

Re: Slow load time - using Optimizely WP Plugin

Hi there,

It's unlikely this is related to Optimizely, though I'd like to investigate further. Please send me via direct message your account ID. With Optimizely, your site shouldn't lag, and any delay to pageload times should be undetectable to the human eye.

Amy Herbertson
Customer Success

Re: Slow load time - using Optimizely WP Plugin

Hi Guys,

Here is the URL I've just set an experiment up on to test the load time:

I'm pedantic about load-time; I hand-coded this page, and for the purposes of testing optimizely out, this one is just a normal variant test (not a redirect)

It is adding 0.7 seconds to my 'Original', and 1.9 seconds to my 'Variant'. This is with MINOR changes.

Considering the load time of the page is only 2.2 seconds; Optimizely is basically doubling my load time.

I do however realise this may be 'unnoticable to the user' - here is a waterfall graph of the 'original' on GTmetrix:

The last item there seems to be the issue; here is the breakdown of that item:

Does this fire after everything else is visible to the user? If so, then I don't suppose there would be an altered User Experience.
JasonDahlin 05-10-16

Re: Slow load time - using Optimizely WP Plugin

According to the waterfall chart, Optimizely took 253 milliseconds to do the DNS lookup, connect, and get the response.


The "log" message you see at the end is the event tracker which records that you have "engaged" on the page (instead of bouncing).  The delay between "xfulltrainingplan.jpeg" and the log event is how long it took for you to click anywhere on the page.  If you had waited 30 seconds, the gap would have been 30 seconds.


On average, Optimizely's response time in the US runs 200-300 ms for me.  Any time other than that is purely a function of the browser processing you have it doing to evaluate your experiments and execute them.

--Jason Dahlin
Analytics and Testing Guru Smiley Happy

Experimentation Hero