While developing Intervals we found the download times being limited by the number of items on the page. To alleviate this, we’ve done two things.
2) We have setup wildcard DNS entries to handle multiple aliases to trick the browser into downloading more than a set number of items. Intervals is using four aliases.
The tricky part with solution #2 is finding the sweet spot for the number of aliases across which to distribute the static content. The Yahoo! User Interface Blog says “Our rule of thumb is to increase the number of parallel downloads by using at least two, but no more than four hostnames.”
Read about it here: Maximizing Parallel Downloads in the Carpool Lane