'ftp localhost' transfer rates are very low


I wonder what could cause ‘ftp localhost’ transfer rate to be so low on
my QNX-6.2 system. There systems itself is basically a standard
PC: ASUS P2B motherboard, P2-333 processor, 512 MBytes of RAM,
4.3 GB Western Digital hard disk as IDE primary master, 32x CDROM
as IDE secondary master, ATI Rage-2 video card, and 3COM
3C905B-TX network adapter. I have allocated the entire 4.3 Gb hard disk
to QNX-6.2.0 (NC edition, downloaded yesterday from QNX web site).
There is essentially no load on the system at all - Photon isn’t
running, no NFS etc. I am running as root. I have created 10MB
file /tmp/foo, FTP-ed to local host, went to /tmp2, and executed
‘put foo’. I got 1.28 Mb/sec transfer rate, which is about 10 times
less then I see with FreeBSD on this very machine. Strangely, if
I FTP to this QNX-6.2 box from Windows, and ‘get’ this file from
QNX-6.2 to Windows, I see more or less decent transfer rate of
2.6 MB/sec. When I ‘put’ this file back from Windows to QNX-6.2,
I see transfer rate about 3.2 MB/sec. Could anybody shed light
on this problem ?