I am downloading two files from Internet. Their combined speed would be around 80Kbps, but the activity monitor shows a huge data transfer, more than 200Kbps. I already turned off auto-update. Below is the screenshot of downloading in the browser and the activity monitor:

enter image description here

Please guide me; what can be wrong here? Maybe my knowledge is not accurate about this.

I am using macOS Sierra 10.12.4.

  • Not sure what you mean by "their combined speed would be around 80KBPS" - how have you calculated a network speed limit from your file sizes? Edit - I think I see, you are seeing ~80KBPS total in the two download boxes but 200 on the network? – Ali Beadle Jul 9 '17 at 6:34
  • @AliBeadle thanks for your comment As you can see in screen shot, LibreOffice is downloading at 3.1KB/sec and cyberduck is at 4.4 KB/s but in activity monitor window in the Lower right corner it says Data received/sec 274KB Why it is saying 274 KB? when i am downloading at combine speed of 3.1KB/s + 4.4 KB/s = 7.5 KB/s – MD Husnain Tahir Jul 9 '17 at 7:08

There is nothing wrong here.

Cyberduck & LibreOffice downloads are displaying their average speed since the beginning of the real download operation.

Activity Monitor is displaying an instantaneous speed which will take into account these 2 downloads, but also all the background network traffic your Mac is always doing (ex.: netbios, Bonjour, ntp). This instantaneous speed is highly variable and depend mostly of this background network traffic.

  • Thanks @daniel for commenting, Cyberduck and libreoffice are displaying instantaneous speed because when connected to 4G internet connection, it suddenly showed speed over 500KB/s, so if the case was average than it should have gone above gradually but not at once to direct 500KB/s – MD Husnain Tahir Jul 10 '17 at 15:34
  • and i am not aware about netbios Bonjour etc, but i have already turned off auto-update in app-store – MD Husnain Tahir Jul 10 '17 at 15:36
  • The 500 kB/s was at startup, wasn't it? – dan Jul 10 '17 at 18:55
  • Yes it at once went above 500 kb/s like in 3 seconds, and never came down untill donwload finished. – MD Husnain Tahir Jul 11 '17 at 23:55
  • Then this is an average value, changing quickly at the beginning and then slower and slower. – dan Jul 12 '17 at 19:30

You cannot do the comparison you're trying to do as you are comparing apples and pears.

It seems like you're comparing apples and apples because the units are the same - i.e. you're comparing kB/s with kB/s.

However in reality data packets on a network are not sent as a continuous stream that can be instantaneously measured as a specific kB/s. In practice programs will measure the amount of data sent over a period of time and calculate an average, which is what is displayed.

As different programs can select difference periods of time to average over - you cannot compare the numbers the way you're doing.

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