performance problems !!

[Frederic.Cambray]

I'm going to replace my NT (pII 450) server by a SAMBA linux (TBird 
1Ghz) one.
I run a comercial production managment software based on corel paradox.
when I do a special treatment, witch processes all the articles, it 
starts normaly,
but after a minute it blocks 2sec and restart 1s until the end of the 
treatment, like if
a buffer was full. The global result is it takes 3 times more than with 
my NT server !!
The two systems have a 100Mbits/s NIS and are connected on the same 
10/100 switch.
I tried samba 2.0.5a, 2.0.7 and  2.2.0_alpha2 and it doesn't change 
anything.
I also tried different kernel, 2.2.14, 2.2.16 and now 2.2.19.
My distibution is a slackware 7.0.
I also tried to change the block size of my partition (1024, 2048 and 4096).
My disks on the linux system are seagate SCSI 10000 rpm whit adaptec 
21160N card.
It takes about 1.30 mn to compile the 2.2.19 kernel.
When I copy files from or to the samba server, it is normal, means fast.

I don't  really see wy this treatment is so slow with SAMBA.

Every suggestion welcome.

F. Cambray