Why am I seeing a long Time to first byte (TTFB) on WebPageTest.org

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    Paul Spencer

    Hi

    This doesn't seem right. Using preconnect allows the browser to peform dns lookup, connect and ssl. It doesn't explain the poor time to first byte. We've done exactly what was suggested and I can see that it has resolved the three items, but I'm still getting very poor time to first byte, anywhere between 150 and 400ms. This is a real shame as Cloudinary is a great solution, but if I can't resolve this it's back to hosting images on the AWS server with below 50ms ttfb.

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    Stephen Doyle

    Hi Paul,

    There are different ways to measure TTFB and different causes of that measurement showing delays; the preconnect option is intended to account for potential delays caused by the DNS and/or SSL lookup and negotiation. 

    With the 'webspeedtest' example above, the primary sources of delays shown in their TTFB metric are usually due to the shared HTTP/2 connection being used (so images requested later may be queued behind those requested earlier), or a delay in the browser dispatching the request for the image due to its position on the page, the relative priority when the browser is requesting page elements, or due to Javascript processing delaying the dispatch while other tasks complete

    Regarding your site specifically, I see you have an existing support ticket and I'll follow up there shortly

    Regards,

    Stephen

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