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Test Your Modem's Throughput

Test your dialup, ISDN, DSL or Cable modem for download throughput (data flow rate), in bits per second measurements.

There is some confusion as to what the difference is between your connect speed and your throughput rate and what the meaning of "baudrate" is.

The connect speed, which is often displayed by mousing-over the Dialup Networking icon in your Windows System Tray, or as indicated by your ISP's sign-on screen, is only valid at the moment when the connection is established.

Throughput, a variable, is the actual data flow rate, in bits per second at any given moment. It is a fluid measurement that varies depending on instant changes in phone, satellite or cable line conditions, web server loads, the compressibility of the files being uploaded or downloaded and the networking configuration of your operating system and any external modem that feeds the Internet signal to your computer(s).

The term baudrate or baud was used in the past by telegraph companies and by manufacturers of facsimile machines and older dialup fax-data modems, to indicate their maximum data transmission rates. The word "Baud" was named for Jean-Maurice-Emile Baudot, the inventor of the Baudot telegraph code in the late 19th century, and was originally a unit of telegraph signalling speed, set at one Morse code dot per second. What baud really refers to is modulation rate (the MO in MOdem), or the number of times per second that a line changes state. The term baud is sometimes misused to refer to "bits per second" (bps), which is the "data rate". Baudrate coincides with bits per second only for two-level modulation with no framing or stop bits. In modern modem technology one "Baud" may contain many signal bits, using special compression and coding techniques to increase throughput.

Read all about the issues affecting your baudrate in Modems 101

There are links below to various sizes of test files, with low compressibility (for accuracy), which can be used to measure your modem's throughput. These test files range from a tiny 15KB, which is best used to test dialup modems that are running at very slow speeds (28000 baud and under), up to 1MB, for testing DSL and cable modems. You should do muliple re-tests with the smaller files to get an average rating of your throughput, and one or two tests with the larger ones. The larger files will smooth out minor speed bumps and give a more accurate reading.

If you know all of this jump to the test links.

If the speed test results indicate consistently low throughput, you may benefit from a tweaking of your modem settings. If you want to try tweaking your modem yourself, there are many online sources of information available. Search Google under the keywords modem tweaking. For example, you can learn more about tweaking your modem settings, and the various initialization codes for different brands of modems, at Modemsite.com.

Dialup modem users can also benefit by signing up with one of the various accelerated Internet services, that speed up the delivery of graphics and web pages, with improvements up to five times the normal speed of display being achieved by some users.

Select one of the links below to test your modem. Use the 15kb (less accurate, but quick), 50 kb or 100 kb files to test dialup modems, and the 250 kb, 500 kb, or 1 mb files to test DSL and cable modems. Please note that a Javascript enabled browser is required for running and measuring these tests. Remember to hit the "Retest" button on the test pages to obtain an average baudrate.

If the reports vary widely each time, or are consistently very low, you will probably benefit from a modem tweak.

Read this note first if you are using a web accelerator, or accelerated ISP:

If you don't use a web page caching service, but you find that you are not getting a fresh page when you try to run a test, your browser is probably the culprit. It is probably saving the test pages to your hard disk (caching). To change your browser's caching behavior you should go to its options, or preferences, and change the cache settings to "check for a newer version every time" a page is requested. Show me how to change my browser's cache settings. You can always change them back after the tests.

Changing your browser's Cache settings:
If you are using Internet Explorer, with a browser open go to the top menu item Tools. Under Tools, move down and click on Internet Options. Under the General tab click on the button in the Temporary Internet Files section, labeled Settings. Click the selection at the top labeled "Every visit to the page." Click OK twice and you are ready to browse web pages without comparing them the your browser's cache files.
Other browsers may have their Cache control settings under the Edit or Tools menu item, in Options or Preferences > Advanced > Cache. If there is an option like "Every time I view the page" select it while running these tests. This should give a fresh result each time. Hide these details and go on to the test links.

Dialup modem tests:
Use this 15kb testfirst, for slow or problematic dialup modems (up to V90/V92).

Use this 50kb file to test typical dialup modems (up to V90/V92) (more accurate).

Use this 100kb link to test fast V90/92 or ISDN modems (very accurate, but takes longer to load).

Broadband modem tests
Use this 250kb test file for extremely accurate V90/92 readings (have a coffee), or for slow speed DSL modems - below 384 kbps.

Use this 500kb link to test medium speed DSL (768 kbps), or heavily loaded cable modems, using a 500 KB file.
Please use only twice in 1 day, to conserve my bandwidth. Thanks!

Use this 1mb link to test high speed DSL, or cable modems, for more accurate results.
Please use only once in 1 day, to conserve my bandwidth. Thanks!

Read all about the issues affecting your baudrate, in Modems 101.


Thank you for visiting Wizcrafts website and for making use of our modem test tools. If you have comments or questions about your throughput results, or wish to hire us to assist you with your modem problems on a personal basis, please use our Comments and Inquiries Form. Our Rates are on this page.

Use Google to search the Web for answers to your questions about modem problems and tweaking.

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