Yves,

Check the following:

1) set maximum packet receive buffers=2000  <-- these can really help even
2) set minimum packet receive buffers=500   <-- with backups!
3) use the novell formulas for memory needs per volume size (and name space).
   Add another 2 meg for TCPIP and 2 meg for ADSM. Actually, Novell told
   me for every NLM you run, you should have 4 meg of memory...even for
   monitor.
4) set tcpbufsize to 32 in dsm.opt.
5) set tcpwinsize to 16 in dsm.opt.