speed

Try with this faq : https://answers.launchpad.net/dcplusplus/+faq/83
Next time please do not set that the language of the question is Italian. Its hard to find - and answer this way...

Unfortunately it does not help. I have already opened 1 port through UPNP behind the router, but it do not speed up.

Segment dowloading seems to slow down the download.

Does segment downloading implies a maximum dowload speed for segment? Is there a way to improve the speed?

Thanks a lot

Segment downloading is a new feature but it doesn't slow down the download speed on a speed of an average adsl connection. While it will be improved in the next release its - just as the normal download - uses the whole bandwith until you set some download speed limit in the Settings (check it if its in default state!)
Have you ever made a download speed test of your connection? (www.speedtest.net) Also many providers limit known p2p protocols and on some bad adsl connections uploads can slow down downloads a lot.
Also you may try to set the manual port forwarding as in many routers UPnP is broken. Check either your router settings and your software firewall (if you use any) for DDoS protection / Internet monitor or similar settings. Their presence can produce slow downloads.

There is a great faq at uTorrent forum about similar problems, read the sticky posts here : http://forum.utorrent.com/viewforum.php?id=11

If none of these helps the best you can do is to wait to the new release.

Where Can I see if there is a speed limit in the download?

Do I need to tune automatic priority?

Settings / Downloads / Limits

Auto priority has no connection with download speeds.

DC Хаблист Список DC-хабов Dchublist

http://dchublist.biz/?do=hubs

Ссылка для вашего клиента: http://dchublist.biz/?do=hublist.xml.bz2

your public hub list url on my DC++ not work.

This public hub list is work and is the best

http://dchublist.biz/?do=hublist.config.bz2

http://dchublist.biz/?do=hublist.xml.bz2 (for DC++ clients newer than 0.4033)