This month we performed several x-cart speed optimizations with great success. As part of our x-cart speed optimization we address 2 components of page loading:

1) Processing Improvements
Processing time is the time it takes for your web server to get the page ready to send to the user before it even begins to load. This includes parsing the php, querying the database, and formatting the page for delivery. The time this process takes is time that your customer will have to wait regardless of their internet connection, so if your processing takes 3 seconds, they can be on the fastest internet connection available (like Google indexing your site) and will have to wait at least 3 seconds for the page to load. In addition, it's processing that can use up a great deal of your server resources bogging down your server causing it to run slower and slower (at that point if you haven't already contacted your host to complain, this is when you'll get an email or phone call from them asking you to upgrade). Improving processing time/speed can drastically increase page loads for all of your users, as well as limit the cost of hosting.

2) Page Load Improvements
Improving your page load involves optimizing the actual content being delivered to your users.

AlchemyAndIce.com
Prior to optimization this site was hardly able to load, sometimes taking 2.5 minutes for a page to load due to the load on the server. As a result the before times were taken with no load on the server to be able to benchmark, and the after times were taken with a full load on the server, indicating just how successful the optimization was.
Processing: 3.15 -> 1.25 (1.9 seconds faster)
Complete Browser Load: 5.58 -> 2.62 (2.96 seconds faster)

CarBodyKits.com
Processing: 3.00 seconds -> 0.94 seconds (2.06 seconds faster)
Complete Browser Load: 5.79 seconds -> 3.23 seconds (2.56 seconds faster)

ForrestHealth.com
Processing: 1.82 -> 1.12 (0.7 seconds faster)
Complete Browser Load: 4.11 -> 2.51 (1.6 seconds faster)

We have more optimizations underway! For more information on how to optimize your x-cart for speed, visit: X-Cart Speed Optimization.