I already put 500 et 5000 to these parameters. So it should works ... but not :-(
In fact i tried to download the ubuntu file you show me and it works very fast (200k/s).
It should mean files I try to download are not so commun. But I don't beleave this.
Indeed, 2 weeks ago, I arrived to download these files very fast (100k/s). What change from this time ? I format my hard disk and past from OSX 10.4 to OSX 10.5. From this change (new os and new amule), it don't wants to download fast again.
I hope you stile have an answer, but if not, thanks a lot for your help.