Regarding mIRC dcc transfer rate

Why is the mIRC dcc transfer rate so slow?I usually download music from mIRC but the downloading speed is like 20-23KB/sec.Where as I get full speed on direct downloads and torrents.If its ports are blocked then how to open ports of mIRC :|

^ Your DCC download speed can't go above the speed limit of sender's upload limit.

In other words, if sender has upload limit of 250kbps then you can't get speed more than this even when you have 1MBit connection.

Allright thanks ...their help channel say that mIRC dcc are always slow :|