Using Webpagetest.org you might be able to determine the cause of your site's slowness.

To Use Webpagetest.org to Determine Site Slowness

1. Go to Webpagetest.org.
2. Enter your website's URL.
3. Pick a test location near your server (North American customers, pick a server in North America. European customers, pick a server in Europe. Asian customers, pick a server in Asia).
4. Select your browser type from the list.
5. Click Start Test.

• If you see First Byte is slow (longer than 1 second), it indicates slowness at the server itself. This could be because of your site's program code or plugins.
• If you see a high number of Requests (more than 100), then your site requires the browser to make a lot of connections to display your site's content. Try to display less content from third-party sites, combine JavaScript and CSS files, use CSS sprites, and enable caching headers to make the browser do less work.
• If you see a high number of Bytes in (more than 1,000 KB), then your site requires the browser to download a lot of files before it can display your site's content.
• If you see an F for Compress Text, you should try Enabling mod_deflate with Your Hosting Account.

You should repeat the test several times over the course of 10 - 15 minutes to get a more accurate representation of your site.

Using Google® PageSpeed, you might be able to determine the cause of your site's slowness.

To Use Google PageSpeed to Determine Site Slowness

1. Go to PageSpeed Online.
2. Enter your website's URL.
3. Click Analyze.

• If your score is an 85 or lower, you have some work to do. Regardless of what's going on at the server, your site will load slowly in the browser.
• If your score is an 86 or higher, your site is probably doing well in the browser, but you might still want to investigate with other tools.
• In the Suggestion Summary, look for High Priority. This is a customized report for your site and each item has a list of the resources on your page that can be optimized as well as some general information on how to optimize them.
• In the Suggestion Summary, review the section labeled Already Done!. This report suggests guidelines to follow to ensure your site is in line with common best practices.

Using Yahoo!® YSlow, you might be able to determine the cause of your site's slowness.

NOTE: YSlow requires Firebug to function. This plugin is also incompatible with Firefox® 5 and above.

To Use Yahoo! YSlow to Determine Site Slowness

1. Install the Yahoo! YSlow browser extension or bookmarklet.
2. Go to your site.
3. Open YSlow or launch the bookmarklet.

   NOTE: On some versions of YSlow you must click Run Test.

4. View the results.

• Go to the Grade tab. YSlow creates a customized report for your site. Each item has a list of the resources on your page that can be optimized as well as some general information on how to optimize them.
• If your score is a C or lower, you have some work to do. Regardless of what's going on at the server, your site will load slowly in the browser.
• If your score is a B or higher, your site is probably doing well in the browser, but you might still want to investigate with other tools.

Using Pingdom, you might be able to determine the cause of your site's slowness.

To Use Pingdom to Determine Site Slowness

1. Go to Pingdom Tools.
2. Enter your website URL.
3. Click Test Now.

• If you see a large page size (more than 1 MB), then your site requires the browser to download a lot of files before it can display your site's content.
• If you see a high number of Requests (more than 100), then your site requires the browser to make a lot of connections to display your site's content. Try to display less content from third-party sites, combine JavaScript and CSS files, use CSS sprites, and enable caching headers to make the browser do less work.
• If you see any 4xx or 5xx errors on the Page Analysis tab, that means your site is referencing a URL that doesn’t exist (cannot be found), or otherwise is generating an error. You should investigate to see which URL is causing the error and fix it.
• If you see any 3xx statuses on the Page Analysis tab, that means you're referencing a URL that is causing a redirect (an additional request). You should investigate to see which URL is causing the redirect and fix it.
• Under the Page Analysis tab, if you see a large amount of time spent on another domain under Time Spent per Domain, this means another site's content could be slowing down your site in the customer's browser. You should investigate this further.

Using lori, you might be able to determine the cause of your site's slowness.

To Use Firefox Plugin lori to Determine Site Slowness

1. Go to Firefox Add-ons.
2. In the “Search all add-ons” dialog box, type lori.
3. Click Add to Firefox.
4. Click Install Now, and then click Restart Now.

• The first set of numbers is the Time to First Byte. This indicates how quickly the first amount of data from your website is received by the browser. Scripts or plugins that fail to send data as soon as a request is made could cause site slowness.
• The second set of numbers is the time it takes for the page to actually load all resources. The higher this number is the more latency your website is experiencing. This latency could also be because of your site's program code or plugins.
• The third set of numbers is the actual page size that is required to be loaded for your site to properly display. The higher this number is the more data must be downloaded for your browser to render the site. In general, you want to have most websites in the range of 300kb – 600kb. If your site is 1MB in size or larger you might experience latency as the server must ensure you’re loading all resources and content to render your site correctly.