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iSight : Check your Broadband Speed

As mentioned in the Title box - there are pages that were written a little while ago by EZ Jim, a poster on the Apple Discussions, who contributes to iSight and iChat Discussions. The words the following pages are EZ Jim's

Use the the Information Column Menu for EZ Jim's pages

Check your Broadband Speed

Both uplink and downlink speeds effect the connection, as do the speeds for each party to the connection. To remove doubt about speed, BOTH you and the ones with whom you experience the problem with should use the Speed Test with at least two of the servers regardless of which test site you use.

Info Mac to Mac: The lowest speed that iChat AV 2.1 can provide video is 50kbps. (iChat AV 3 requires at least 100kbps.). Below this figure, iChat will give error messages.

You should get smooth Mac<-> Mac video with iChat AV 2.1 if all uplink and downlink speeds for both ends of the connection is above 99 Kbps. ('real' world speeds, as measured by the test not as reported by the Connection Doctor). If ALL your numbers are well above that, you can probably safely assume that connection speed is NOT causing your pixelated video.

iChat AV 3 does not normally pixelate as broadband speed decreases. Rather, you may get error messages and lose ability to connect. If you can connect, the session looses audio and video stability and the picture becomes "soft."

iChat AV 3 requires at least 500 Kbps both up and down for best quality multi-party video connections. These requirements apply to all participants in the iChat  AV  3 video connection. Speed requirements for the multi-party video connection host are even higher. See Mac OS X 10.4: iChat AV system requirements for details.

My current broadband is rated up to 9 Megs down and 1 Meg up, thus doubling my previous bandwidth. The increased speed significantly improves multi-party video quality, especially in videos I host with participants who have similarly speeds.

Mac <-> Mac connection speeds can be in the 80-100 Kbps range and still work reliably, though quality will decrease. Of course, more speed (up to about about 500 Kbps) gives better results. Beyond 500 Kbps, more speed seems to make little difference for iChat AV 2. in my experience. (As noted above, speed requirements for iChat AV 3 are far higher.)

Info Mac to PC: Mac <-> PC video needs higher connection speeds, at least 150Kbps for smooth video. I have connected with PCs as low as the 110-120 Kbps range, but the video is usually of poor quality, pixelated, and unstable. See Mac Video Chat with PCs for more suggestions on improving your results once you both have adequate broadband speed.

Do the tests. Do not just assume that you are getting the promised speed from your DSL or Cable ISP. Broadband speed promised is not always what is delivered. You can use this DSLReports' Speed Test. You can use this ADSLGuide's Broadband Speed Test if the first one is too busy. There is also bpl SpeedTest. To ensure accurate results, follow the instructions at the site you use.

Using the data you gather with Speed Test, if either of your ISPs are NOT delivering what you are paying for in your service billing, you will have FACTS to use to get resolution. If the speed IS all that is advertised but it is below the recommended minimums, you may want to upgrade your service to get better video between Mac and PC. Only you can decide whether spending money for a higher bandwidth service is worthwhile.

These numbers assume you have only one computer on the connection. If you have more than one computer sharing the connection, you will need the above bandwidth for each; i.e., if you have 2 computers using the connection simultaneously, multiply the requirements by 2 to be sure speed is not your problem.

If your test indicates that speed is not the problem, post your (uplink and downlink) speed numbers and details of how you connect your Macs to your ISP in iChat AV Discussions. (Make and Model of your modems, routers, and wireless equipment as well as how many computers share each of your connection.).In some cases the country you are talking from and to would be helpful.


Written By EZ Jim

Made on Mac
Made on a Mac®

© 2005, 2006 EZ Jim
Updated September 2006

© 2005 Ralph Johns: Edited 24/9/2005, 5/5/2006
Updated September 2006. Moved to Gargoyles Mar 2007

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