resouces loaded sequential instead of paralel with chrome and spyd

Hi,

I have some weird results that I don’t understand.
http://www.webpagetest.org/result/140221_GY_d35f89cf82aa3dfe9638a12239681a71/1/details/

http://www.webpagetest.org/result/140221_P6_7ed18ccd6cce62d8b6d82caad863b0c9/1/details/

The test shows that all resources (jgp, webp, css) are loaded after each other and almost no parralel downloads. That is, that they do start simultaniously (start offset) and then have a long time to first byte. Is the time to first byte waiting on the download of the previous resources or something?

I don’t know if the webpagetest makes use of SPDY, the webserver checks the client if it’s spdy capable and then sets a head for the backend server which has mod_pagespeed. If the client is sdpy enabled all resources go over one domain. If not, then it’s sharded across 3 hostnames.

Disabling mod_pagespeed does not help, same issues. Same applies to removing varnish caching from the chain.

If I test with my client at home, with a 10Ms latency the site loads in about 300Ms total. The webpagetest were done without bandwidth limitations (native connection)

I checked if it would be a result of latency amplication, eg more latency the bigger the problem. I checked all equipment for duplex mismatches and none were found.

Some webpagetest servers I used have a latency of 1Ms to the website, they also show simular results. Why these defer from my home situation? Running test with IE seems (with regards to the waterfall) doing better, having the domain sharded.

However, on the sharded setup I have TLS negotiations on a whole lot of resources, not just 3 times (for the 3 hostnames in the sharding), but I guess that is due to the opening of new connections.

The results can vary a lot on different tests while not changing the servers.

Any suggestions?