Why does Windows 7's Resource Monitor indicate 12 Mbps of Network I/O while it also indicates ~10MB/s of Network Activity?

Question

I saw the following:

Why does Windows 7's Resource Monitor indicate 12 Mbps of Network I/O while it also indicates ~10MB/s of Network Activity?

Answer 1

I suspect that the 12 Mbps Network I/O and 0% Network Utilization values between the two tables are instantaneous --i.e., they display the values "right now"-- while the values within the columns with units of B/sec are actually "average B/sec over the past 60 seconds". You mentioned that the top-right graph also shows basically nothing from t-minus 42 seconds to zero time/"right now"; a 12 Mbps line on that graph would be basically indistinguishable from the x-axis and lines up with the instantaneous theory.

Further, the top-right graph has approximately 110 cells, and about 8 or 9 of those are filled (give or take). At that rate, the "average" Mbps for the past 60 seconds would be 1000 Mbps * (9 filled cells / 110 total cells) = 82 Mbps, or about 10 MBps, which approximately lines up with the given Total (B/sec) in the "Processes with Network Activity" table.

Finally, this link for Windows Server 2008 (I know that's not Windows 7, and I don't know if perfmon and Resource Monitor are the same thing) also indicates that the columns are over the entire minute:

The total bandwidth (in Bytes/min.) that is currently being sent and received by the application instance.

Granted, that link also says that the units are Bytes/min, but... that's the closest I found to documentation on something around Windows 7's age.

You could take more snapshots of the resource monitor with different conditions to see if my assumptions still hold.

Answer 2

Because the list views display a smoothed/delayed value. You can easily test this by starting a large download. Compare the download speed as indicated by your browser with the Resource Monitor display. It will (very) slowly ramp up.

When you then cancel the download (instantly bringing the bandwidth use down to zero), the last indicated connection speed will stick around for a very long time.

Check this example:

To demonstrate, I downloaded a file, it went ~40 MiB/s. This is visible in the upper right graph. I then cancelled the download, which is again clearly visible in the graph. Yet, Firefox continues to be displayed. As Preston Maness already deduced in his answer, it sticks for ~61 seconds after the transfer is over.