Thanks a lot for the link and contribution to the thread. The never ending quest to make Magento quicker continues

In our case best trafic optimization came through installing Fooman Speedster to minify CSS and JavaScript, but unfortunatelly Speedster free version is uncompatible with allocating different domain names for Skin and JS, http://www.magentocommerce.com/boards/v … ad/200056/ and SpeedsterEnterprise is required.

Another good practice is disallowing Cookies for the non-php aliases (Media, Skin and JS)

Follow http://twitter.com/theTestTube

Any reason for this?

Thanks!

Overview

You can speed up your loading times on unencrypted pages of your Magento store by utilising parallel connections.  Most browsers are limited to making only a small number of connections to a domain in parallel, by fooling the browser into thinking its loading objects from several domains on one page it will increase the number of concurrent connections to the server.

Note : This only works on unencrypted pages, for pages on your store that use SSL encryption this would be counter productive as it would produce unauthenticated content.

Complexity

Easy

Suitable for:

Shared Hosting
VPS Hosting
Dedicated Hosting

Requirements

1) Access to your Magento Administrator Panel
2) Access to your Hosting Control Panel
3) Your site's nameservers are assumed to be with us
4) You are not using the Fooman Speedster extension, as it doesn't seem to honour Magento base URLs (Please be aware that the Fooman Speedster has issues if you try to disable it : See here

Howto :

(As ever Nublue recommends that you backup your Magento store using your Hosting Control Panel backup utility before undertaking any configuration changes on Magento)
1) Login to your Hosting Control Panel
2) Navigate to your Magento domain
3) Click on Domain Aliases

4) Add the following domains using the image as a guide replacing domain_name.com with your domain.  See the note below if you don't have a Add New Domain Alias button :

css.domain_name.com
js.domain_name.com
media.domain_name.com

5) Test the aliases are working by navigating in a browser to the domain aliases you've created.  You will either see your store on that URL or it will forward to the URL of your store.  So long as you see your store in the end its working!
6) Now login to your Magento Admin Panel
7) Navigate to System -> Configuration
7a) For Magento multistore configurations only : Choose your configuration scope using the dropdown.
8) Choose the Web option on the left navigation bar
9) Ensure you are only looking at Unsecure Base URLs
10) Change the following replacing your_domain.com with your domain, and ensuring you replicate all trailing forward slashes (use the image below as a guide) :
Base Skin URL         Use : http://css.your_domain.com/skin/   
Base Media URL         Use : http://media.your_domain.com/media/
Base JavaScript URL      Use : http://js.your_domain.com/js/
DO NOT make any changes to Base URL and Base Link URL.

10a) For Magento multistore configurations only : Untick "Use Default"
11) Save your configuration changes.
12) Refresh your Magento cache (either using our Control Panel option or using the Magento Admin panel Cache refresh option.
13) You can test the results here :
http://www.nubluemagento.co.uk/ (With parallel connections)
http://furniture.nubluemagento.co.uk/ (Without parallel connections)
This is a multistore setup with one store view using parallel connections and one store view not using them.
You can also test using the Firefox extension Firebug, open up the Net tab and load the above pages to see the parallel connections in action.

Please note : Not all web based page load speed tests replicate browser behaviour, so its quite possible and quite probable that they will show no change across the two sites.

Possible Issues :

Some older customers may not have access to the Domain Aliases or Add New Domain Alias functions in their Control Panel, if that is the case simply email in to us at support and we'll get your permissions updated.

Reversing the Change

Should you wish to reverse the settings, here's what a vanilla Magento configuration looks like :

[Edited 04/06/2010 to add warning regarding disabling Fooman Speedster module]