pagespeed queries... maybe a bit off topic?

Hi folks,

I’m investigating a few new technologies to get the best out of my platform when delivering a Magento eCommerce website. Hardware is a VPS running on a busy little blade server, so I don’t expect that much out of it in absolute terms, just to get a feel of what works best.

Here’s a problem I’ve got at the moment… timeouts - and I’ve tried a few different testing instances ). Any ideas why?

ngx_pagespeed on:
http://www.webpagetest.org/result/150923_JQ_19FC/

ngx_pagespeed off:
http://www.webpagetest.org/result/150923_DX_19XV/

I’m researching what the problem could be, but if anyone has come across this, please let me know!