I would know how to see real clients both download & upload speed.
Only via bandwith server tool?
best way is to use some other tools like: iperf. A tool which transfers traffic between 2 computer. if you use the bandwidthtool on the routers directly it might be that you max you the router cpus ( depends of hardware ) and your test result is inaccurate.
you mean I will use 100% of cpu usage during bandwith test?
Yes that can cpu load is big with bandwidth test.
yeah that is what i mean. especially when you use the bandwidthtool in tcp mode it took a lot extra cpu cycles to do all that tcp stack stuff. you know packet ordering and so. just forward a packet from one interface to another is much easier for the router. iirc a test with bandwidth tool (tcp mode) from a groove to a groove was less than 40Mbps while doing test with other tools where the grooves just had to forward the packets was full linespeed.
i’m not really using the mikrotik bandwith tool anymore. my suggestion iperf
is there any wiki for iperf?
iperf is a cli tool. on most linux distributions you can install it with the packetmanager ( e.g. apt-get ). for info about usage just check http://iperf.fr/. there are also examples and a windows version.
You have also a windows version http://www.iperfwindows.com/download/IPERFforWindows-Charts-UI-Demo.exe
yeah, everyone knows what iperf is.
I don’t know how to set Routerboard as client.
i would not use a routerboard as client as it sophisticates the result. most routerboards are not powerful enough for all the tcp stuff.
Look this for how use iperf i made it on my website
http://www.wirelessinfo.be/index.php/linktesten/pages/iperf
I hope this help you
OMG it’s not in english 
Have translated it as best I can
http://www.wirelessinfo.be/index.php/linktesten/pages/iperfe
thank you.
I got some other questions:
-it says javaw not found
-does it works between mikrotik & ubiquiti devices?
You must install java first
http://java.com/nl/download/