I'm trying to improve my site's performance. I've installed the Firebug | Yslow! (http://developer.yahoo.com/yslow/)firefox extension and have implemented some of the recommendations such as moving CSS to the top and JS to the bottom and so on.

I was wondering if I would get any performance boost by putting some of my images in a subdomain. For example, if my domain is: domain.com, I would create a subdomain images.domain.com.

My understanding is that the browser would be able to download from both areas in parallel (http://www.websiteoptimization.com/speed/tweak/parallel/). Instead of getting two objects from 1 domain, it could fetch 2 objects from each of the 2 domains.

Thoughts?

prodport,

Putting your images on a subdomain may help, but it could also hurt depending on a few things. One thing to consider is the size and number of images. If they are fairly small, and there aren't a lot of them, putting the images on the subdomain could help because the data would be able to transfer simultaneously with the page itself.

If you have larger images or many small images, putting them on a subdomain could slow things down. This is because each images could potentially generate a new Apache process. Because there is a set limit in the number of processes Apache can run, having too many going at once will significantly slow things down if you have more than a couple of users requesting data on the site at once.