[gentoo-user] Slow samba transfers from gentoo to gentoo, any way to improve them?

[App Des]

I have a gentoo server running stable fully updated, and I share a folder
with samba on a gigabit network.

The client dual boots Gentoo (stable again) and Windows 7.

Under windows 7, getting a file from the server achieves around 70MB/s

Under Gentoo, using gnome gvfs, it can only achieve around 30BM/s. I though
that gvfs must be slow, and I tried manually using cifs mount, but again the
speed dropped further to ~18mb/s.

Both the client and server happen to use exactly the same network card, so
it must not be a network driver problem as all my gentoo systems use the
same kernel, as the Windows performance is acceptable, something must go
wrong in my client-desktop gentoo, any ideas?