Samba connection 6x faster when netwatch is running

Hello,
I have a weird problem with samba.

I use cp to copy files from my Linux-Laptop to a DVD-Drive on a machine
running Windows 98.
The connection speed is really slow, only ~ 50 kBytes/s.
Yet when I invoke netwatch the speed jumps to ~ 300 kBytes/s which is ok,
keeping in mind that I use a really slow PC (120 Mhz) and Linux does not
support my ide-chipset (only experimental, its an Opti Viper 82C558).

The boost in speed is real, since the directory on the Windows PC gets
aquivalently bigger too.

Any idea how come invoking netwatch boosts the connection speed?

I don't know exactly what type of network card is installed in my Compaq LTE
5200 Docking Station, but I found a posting from the developer of the
NE2000 module indicating that it supports my network card.

I don't expect to get much more then 300 kBytes/s since at that speed the cp
process (and the netwatch process) already use most of my processors power.

Any ideas? Can iptables have something to do with this?

Configuration:
Debian GNU/Linux 3.0
Linux 2.4.21

samba:
Installed: 2.2.3a-12.3
Candidate: 2.2.3a-12.3


Pentium 120 Mhz
72 MB Ram
20 GB HDD (only PIO, support for DMA is only experimental)
Network Card is Ne2000 compatibel says the developer of the Ne2000 driver.

I appreciate any help.

Regards,
Georg Klein