FreeBSD 4.8 on WD1200JB - dissapointing access times

[Joel V.]

Hello!

Now here's the case. I have this machine running FreeBSD 4.8:

P4 2.4Ghz
512MB DDR333
Intel D845PESV motherboard
Intel Pro/100 S nic
WD 120GB hdd (8mb cache)
3COM officeconnect 100Mbit switch
(About 7-8 people using the fileserver)

The problem is that I'm experiencing rather dissapointing access times when
connecting with a winxp/win2k client to the FreeBSD box running samba.
Sometimes it can take up to 5-6 seconds to display the content of a
directory. However, during the day, when people are using it all the time,
such lag seems to occur not very often. Why I'm a bit suspicous is this - I
have another fileserver running in another firm, which serves more people
(about 10-15), yet has no such lag:

Athlon XP 1900+
512MB DDR266
Abit KR-133A motherboard (I think...)
SMC nic with RTL chip (serious suckage)
IBM 120GXP-series hdd, 80GB /w 2mb cache
some el cheapo switch (trendnet? trendmicro? trendtrend? or something)
Running FreeBSD 5.1

The average read access of the IBM drive is 8.5ms and of the WD drive 8.9ms.
(As far as I know, the average latency for both is about 4ms.) Can this 0.4m
really make that much of a difference? The 4.8 machine seems to be in a
better position no matter how you look at it (cmon, RTL chip?!), but still
it does not experience this annoying lag. When I'm behind the the server
physically, all is OK with both machines, no lag whatsoever behind the
console. SSH connections are also OK.

If you can help me with this one, please send mail directly to me, I'm not
in the list (however I try to read it as frequently as I can).

Joel V. (joel at spirit.ee)