I have in Tixati only 1 download, I removed the restrictions that I knew, but the speed does not want to rise above 600 KB.
Tell me what to do, and sorry for the bad English =)
Screenshot: http://www.screencapture.ru/file/315A2FCD

what internet do you have from your ISP? (in mbps)

Screenshot: http://www.screencapture.ru/file/e78d9B2B   (In KB/s)
OK.... how to increase Internet speed?
But i download film with speed ~ 2000-4000 Kb/s
How do explain it?

Three downloads with the same result, but there is no limit to the "outgoing bytes"
Screenshot: http://www.screencapture.ru/file/25688Ce0

The speed from my ISP do not know, so I decided do a speedtest
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Speedtest:                                                              
DOWNLOAD:   4.9 Mbit/s      
UPLOAD:     5.08 Mbit/s                              
PING 13 ms                            
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By Max

5Mbit/s is 640KB/s, it seems you are downloading at maximum speed already.

"But i download film with speed ~ 2000-4000 Kb/s
How do explain it?"
For example: http://www.screencapture.ru/file/fF41B613

Sounds like you connected to a local seed on the same ISP node or LAN as yourself.

Some ISPs have *MUCH* faster speeds to local area than to the rest of the internet.
Typically, these are fiber WANs covering a city.

I'm not sure that this is either due to the problem.
Important: The limit does not depend on the number of downloads, but it (the limit) can "kill" a strong seeder.