There is nothing to check, math is simple, no matter what filezilla shows in speeds,

1900MB / 21 second = 90.4MB/s <--which is still fast as hell
There is no 171, or 400MB/s

There is no wrong or faked images here, it's just filezilla issue.

If you saw those numbers, it has nothing to do with actual speed, it is just a way how filezilla refresh speeds, where you, in one moment get 60MB/s and in next 171.

This is because time of refreshing is =/= 1 sec sharp, it varies from 0.5 to 1.5 sec
So, simply said you get for example 60MB/0.5 sec and in next 171/1.7 sec

This is caused by caching data from HDD into buffer, where, every time data is read from HDD, speed drops, and when it burst from buffer, speed jumps, but only because there is lag in speed measuring.

Also, no regular SATA disk can read more than 100-110MB/s
Only expensive SAS or SSD disks can go 2X-3X times of that.

Well, people learn as long as they are interested in learning.

Btw, same thing is happening with zooms uploader.

While it shows 130-180MB/s, which is impossible on 1gbit lane (even with SAS disks I have), real speed doesn't go that much, and real speed is shown in Task Manager / Networking / Bytes Sent Per Interval.

ONLY this shows you real speeds, none of other programs can show you more realistic speeds from Networking, not DUMeter, not some networking tools, because only there refresh rate is 1 sec +- 0.1 S