safari slow load web pages

Hi

I am using safari 8.0.5 on Max OS 10.10.4 on a Mid 2014 macbook pro. The problem is that safari is very slow to load web pages, especially if they are clicked through for an email. The progress bar goes about half way along the toolbar and then seems to halt. If I click in there toolbar window to reload the page it often comes back much quicker. I thought this was a DNS problem but have tried it with the DNS provided by by internet service as well as Google and OpenDNS servers with the same problem.

System details below: