Cable Modems
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Cable and DSL Modems

The modem speed test pages are designed for, and tested on, ordinary analogue dial-up modems, and ISDN modems. Results of tests for other 'high speed' modems, such as, cable modems and DSL modems may be in-accurate. For example, tests between two computers over a simple ethernet (10Mbps) network indicate a throughput of less than half the theoretical maximum. However, it is possible that this in-accuracy is due to increased overheads which occur at such a high transfer rate. Unfortunately, I don't have access to cable or DSL modem technology yet, and therefore must rely on feedback from cable and DSL modem users.

Cable and DSL modem results received

During January and February 2000, I received just under one hundred test page results from Cable and DSL modem users in response to a user poll.

Most users reported throughputs between 5Kcps and 100Kcps (about 40Kbps to 800Kbps), with notable peaks around 25-30Kcps and 50-60Kcps.

Few users indicated what throughput they expected. Of those who did, most 512Kbps users reported 30-60Kcps (240-480Kbps), 1Mbps users reported around 30Kcps, while 10Mbps users reported around 1,000Kcps.

Some users commented that their throughput was lower by a factor of up to ten times during the day and other 'busy' times.

Ed Reardon, who uses a "640K" DSL connection from BellaAltantic.Net in Washington D.C. wasn't getting the results he expected, and found the test page invaluable in correcting a problem that he discovered. He wrote,

"My experience MAY give some insight to others, if you care to use this info. A friend who also has a BAC/DSL connection passed on to me a website that provided information about how to tweak Windows95 to get the most out of a DSL connection.   I'm no techie, but it seems the updates did two things:
  1. Got updates from Microsoft to tweak W95 for use with a LAN-type connection (instead of just dial-up modem), and
  2. Implemented changes to my Windows system settings to take advantage of same.
After I made these changes, I went back to your test page and, instead of getting readings of around 30/33, I immediately got download readings around 50/55...

...It seems there MAY be some problems that we old users of Windows95 don't have all what we could/should to take advantage of the Ethernet/LAN type communications that DSL uses.

Here's the web site I was directed to...  ...Navas Cable Modem/DSL Tuning Guide ."


With a large variance in test results, it was not possible to determine the accuracy of the test. Many service providers advertise 'speeds up to 100 times faster than a 28.8Kbps modem', however, most users reported that their best speed was 10 or 20 times faster than a 28.8Kbps modem. The tests don't measure your speed when downloading content served by your service provider, which won't be affected by Internet congestion, but the test may still be a worthwhile benchmark for cable and DSL users who wish to test download speeds from a graphic ladden web page on a remote server on the Internet.

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