High cpu load with rtorrent

[laizzn]

I have very high cpu load (>100%) when rtorrent is downloading some torrent.
rtorrent uses nearly all the cpu (top: rtor 20 0 3031220 556204 397720 R 103.3 3.5 126:32.90 rtorrent main) when downloading at 28Mb/s.
I guess that because of this high cpu load, the speed does not go beyond 30Mb/s..

I have a Ivy Bridge, i7 (Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz), which should suffice I think, and I haven't had this problem with Transmission.
Also, with the Sempron 145 I had before, and which is much less powerful, rtorrent also used >100% of the cpu load. I guess every resource you got gets used up.


I already tried switching curl ssl from openssl to gnutls but it did not get much better..So I think something else is wrong...?!