I've found several posts in the past discussing how host location may or may not affect speed of loading of a website and the consensus seemed to be that unless there was a huge distance separating you and your host (like maybe someone in EU using a host on the west coast of the US), generally host location won't necessarily affect speed much as long as they have good connections. Feel free to correct me if I'm wrong though
I'm wondering though, how does host location affect rankings in search engines. Like if I am CDN with a .ca domain and go with a US host, or US with a .com domain and go with a CDN host, will that have a significant, or any impact on ratings.
I don't believe it could affect it in a negative way. I've almost always hosted my sites in the U.S. (from Belgium), and never had noticed any issue involving ranking. For some time I was with a host in the Netherlands; after moving the site back to the U.S., nothing changed.
Google are measuring page load speed as an input into their algorithm but the few hundred milliseconds added by a packet travelling a longer route is negligible compared to any database lookup and slow server problems.
I would worry about the geographic location after you have optimized all queries, removed any serial loading dependencies , implemented caching, ensured all files are being served compressed, you have minified all your js and css
Have a look into firebug (add on to firefox) or one of the other developer tools that come with most browser and look at the network tab. This should have a graph that will tell you where your queries are loosing time and you can focus on these.
Basically, if you're using a ccTLD, then it doesn't matter. If you're using a generic TLD, then it can.
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