Why You Should Avoid Zoom For International Calls

An in-depth analysis of videoconferencing systems has exposed that on foreign calls Zoom calls may be even more laggy than those from competing providers.

The SamKnows research that conducts network monitoring for several Uk internet networks and telecoms authorities measured the efficiency of many major video conferencing apps, including Zoom, Skype, Google Meet and others.

The study found that while most services of videoconferencing have servers scattered around the world, all servers of Zoom are based in the U.S. This may result in slightly larger lags on video calls while participants are located outside the U.S.

SamKnows used white boxes linked to some of UK’s largest internet networks to compare several of the major video conferencing facilities. Although all of Zoom’s nearest rivals had 20-30 millisecond latency, Zoom had an overall latency of around 135 milliseconds around five or six times less than its rivals.

A graph showing lag on major videoconferencing services
Sam Knows Data

“Most of the services have latency between 20ms and 30ms,” the SamKnows report states. “Traceroutes to their IP addresses show hosting locations varying between the U.K., Ireland, Amsterdam and Frankfurt. These are fairly typical hosting locations for serving a western European market.”

“The one exception in the chart below is Zoom, which sees average latencies of around 135ms. We found that Zoom was using audio/video relay servers in the U.S. In fact, we found that this was true for every country that we tested from–not just the U.K. Zoom are currently relaying all audio/video traffic via their servers in the U.S, regardless of the country the user is located in.”

SamKnows captured a video call made between two users in London, using both Zoom and Google Meet simultaneously, to see what impact the increased latency will have on call results. By detecting when one caller blinked during the call, SamKnows was able to establish on the same call the Zoom was around three video frames behind Google Meet.

“These small differences may account for users accidentally talking over one another more frequently when using Zoom, and other similarly small frustrations that are due to increased delay,” the sam knows report claims.


“It is also worth noting that our test call used two users in London, which both had a latency of 135ms to Zoom’s U.S. servers. Had we tried a Zoom call between two users in Australia or parts of Asia, then the difference would likely have been more significant.”

On the flip side, calls made solely between U.S. participants are unlikely to experience a far worse latency than those made on any other service.

Chief Technical Officer SamKnows, Sam Crawford, claims several of Zoom’s smaller competitors including WebEx and GoToMeeting still have “broad foreign reach” with servers on a few continents.

Crawford was also swift to blame Zoom for “how difficult it is to note the lag” in calls, adding.


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