For example, my URL is:


For SEO, PageSpeed and Server Tweaking for ultimate performance, and speed, my code places static files like JavaScript, CSS and Images on my CDN:

www.site-cdn.com (seperate server)

Will it help if I have a script which randomly loads one of the these:

www.site-cdn2.com (on the same origin as cd1 but different dedicated IP) 
www.site-cdn3.com (on the same origin as cd1 but different dedicated IP)
  • Just one other consideration: if a user might potentially get different CDN domains as they move between pages on your site, you're adding DNS lookups, which will have a negative effect on speed (albeit a very minor one). Sep 26, 2011 at 15:27
  • Yes, I know this but I over looked this scenario. I don't think it will have major issue .. especially if they both Cache, have LiteSpeed, Nginx, APC and File Compression on them.. that way, the user has cache both versions of files on the URLs ?? Thanks Sep 26, 2011 at 16:00
  • Nginx, APC and file compression have no effect whatsoever on the time it takes to do a DNS lookup; and yes the user would need to download multiple copies of the same file if they get a different CDN host. Really the only reason to go down this route is if you need to spread your load between CDNs, so I'd stick to one. Sep 26, 2011 at 16:07
  • Thanks for the replies, above and below. I thought APC and Nginx improve speed. Nginx, is the fastest server software operating system on the planet ATM according to some. For static files, Nginx and litespeed and APC type force hacks make it extra fast. Sep 27, 2011 at 9:31

1 Answer 1


This won't really have an effect on your SEO as page speed really only affect the slowest 1% of web pages out there. Basically a slow web page may be penalized but a fast web page will not receive a bonus.

In your scenario, splitting up which CDN you use also shouldn't make a difference since the files will be coming from the same server. If your different CDN addressed were located at different parts of the country or world then it would help your page loading performance as the user would get those static files from their local CDN rather then from one potentially on the other side of the globe.

  • Thanks. With regards to the mention of it not being a bonus, this appears to me as a matter of opinion now: google.co.uk/search?q=pagespeed+seo - I realise Matt Cutts is full of crap for the real SEO gurus but there are other major players backing that pageSpeed effects SEO big time. Sep 26, 2011 at 14:15
  • So you believe pure speculation from people with no insider knowledge whatsoever over what Google themselves say about their own service? Sep 26, 2011 at 15:25
  • @Tim Fountain if your directing that to me.. Did you bother reading my message? Clearly not. I said that Matt Cutts can seem to be a little misleading - backed by some SEOs I follow. However, PageSpeed and compression has a great impact on results IMO through projects I have worked on time and time again and CDN usage helps too. There is a saying and Google adapt this. What helps people.. Helps business.. so applies the same to UI/UX.. Sep 26, 2011 at 15:58
  • There's a big difference between being "full of crap" and "a little misleading", but sorry if I misunderstood you. Improving site speed is a great thing to work on because it benefits the user, and if you've seen better rankings then great. But personally I have seen no evidence to disprove the info in John's answer, which is what Google themselves have said. Sep 26, 2011 at 16:20

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