How to Time Sites
Now test your own site and all your bench mark sites for download times, and make copious charts of the results. I've tried different methodologies for timing page downloads, and finally hit upon the best trade-off between time required and accuracy of results. To get meaningful comparisons with a minimum amount of effort, use this method:
First, create a list of pages to compare. Then sit down at your test computer, clear the browser cache (unless the test calls for having certain images in cache), and load the first page. Record the time lapse. (I use my trusty dual-button, quad-mode Precise Synchrosport 910 stopwatch). Clear the cache, reset your stopwatch, and load the second page. Clear the cache and load the third, etc. After loading each page once, start over with the first one and go through the list again. After enough trials (I usually do five to seven), throw out the high and low times for each page to account for network hiccups or human error. The three to five remaining times are usually very close together. Compare the average for each site, like this:
Why don't I time the first page five times, then the second five times, then the third? Because on the Internet, server peaks and network traffic jams come and go from second to second and minute to minute. By interleaving the contestants' trials, I evenly distribute the problems (whether at one of the sites, on my ISP, or somewhere in between) throughout all the data.
Even then, any site can have a "bad hair day" (when its performance is unusually poor). So you need to perform comparative timings repeatedly, at different times of the day, different times of the week, and different weeks during your project. This also keeps you in-the-know about the competition's changes and improvements sometimes a site that was slow in April starts kicking butt in May.