Determine real bandwidth usage

Hi, i need to determine my real bandwidth usage in windows, but i find discrepancies when comparing different methods.

Cacti says im using 3Mbps I/O:
https://s31.postimg.org/di0itfmzf/Band_Cacti.jpg

Net Limiter says aim using 2Mbps I/O
https://s32.postimg.org/pcf94frnp/Band_Net_Limiter.jpg

Resource monitor says im using 2Mbps I/O
https://s31.postimg.org/n4m43hisb/Ba...ce_Monitor.jpg

Task manager says im using 3% of 100Mbps = 3Mbps I/O (I think so)
https://s31.postimg.org/b40o2rbdn/Band_Task_Manager.jpg


This differences increases and are more noticeable when bandwidth usage increases. Which method should i trust and why this differences?

Thank you!

This should be quite normal.
Speed test is just a guide, and it depend on which server the speed test use.
Also it depend as not only you are using, many others are also accessing the network.
There is no such REAL Bandwidth.

I never said that i want to know my internet speed... I want to know exactly the bandwidth that a connection is using and that i don't know why if i use 4 different tools they give me different results. In the exaple i gave theres only 1Mbps I/O of difference, but as bandwith usage increases, that difference increases even more, for example last night i had 14Mbps I/O with Cacti and task manager, and 10Mbps with Net limiter and Resource monitor.

Download speed depends on where you are downloading from eg I may get 62 Mb/s d/l from Microsoft, but only 0.5 Mb/s from a dodgy movie site. Ditto upload - I get 18 Mb/s u/l to Vimeo, but only 8 Mbps when u/l to Dropbox.

I concur with Barman58 - measure max speed at speedtest.net. Addgadgets have a good realtime desktop network gadget -

Windows Desktop Gadgets - Network Meter Gadgets Version 9.6

I find using a 3rd party firmware, such as tomato, on my router gives me the best stats on bandwidth usage.

Someone may have said this or maybe it's not what you are asking. If so.. sorry.