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Measuring Load Time for a Web Page

  • Article

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1

Measure your first-access and second-access page-load times by using the procedures that follow.

To measure a Web page's first-access load time

  1. Set up your WAN simulator to represent your 50th percentile domestic user. For example, your settings might be 60 milliseconds roundtrip delay, 50 kilobits per second, and no packet loss.

  2. Set the site that you want to test as the default home page for your browser.

  3. Browse to a site other than the one you are testing.

    If you are still on the test site when you clear your cache, the site refreshes after you clear the cache, reloading the files that you want to clear.

  4. Clear the cache of all files by doing the following:

    1. On the Tools menu of Internet Explorer, click Internet Options.

    2. On the General tab, under History, click Clear History.

  5. Close your browser.

    You must close TCP connections between tests, or your tests will be affected by TCPs slow-start algorithm, which retains the window size from the previous page load, producing inaccurate results.

  6. Start your Network Monitor capture.

  7. Open your browser to the test site (your new home page).

  8. Stop the capture when the page is fully loaded and run Network Monitor. Determine how much total time elapsed while the page was loading.

  9. Copy your data into a Microsoft® Excel worksheet for further analysis.

Important

Do not use CTRL+F5 (refresh the Web page — regardless of time stamp) as a substitute for this procedure. Although using CTRL+F5 is similar to this process in that it forces a full reload, it does not disconnect the TCP connections before the new page load.

When you test a Web page for its second-access load time, you can use files that are saved in the client's cache.

To measure a Web page's second-access load time

  1. Use the same WAN parameters and browser default settings that you used to determine first-access load time.

  2. Close your browser without clearing the cache.

  3. Restart your Network Monitor capture.

  4. Open your browser to the test page.

  5. Stop the capture when the page is fully loaded, and measure the time from the first TCP SYN from the client to the server, until the last byte is received.

  6. Copy the results to a second Excel worksheet for further analysis.

Important

Do not use F5 (refresh the Web page) as a substitute for this procedure because it does not provide the same results as a second page-load. Using F5 forces Internet Explorer to check the date on all cached files regardless of whether the dates will expire in the future.

After obtaining a page-load performance profile, analyze the data and remove obstacles to the pages efficient performance by using the information in Optimizing a Page-Load Performance Profile. For more information about first-access and second-access page-load times, see Obtaining a Page-Load Performance Profile.