Printer: HP 2550 Color Laserget on USD or Parallel (doesn't matter)

Network: Linux Redhat 7.2 Server for Gateway, FileServer, PrintServer anf Samba PDC NT Domain Server.
WindowsXP and 98 computers

I installed the printer and it works wery well from the local computer.
I shared it and it can bee seen from the other Windows machines.
It can be installed without any Errors or Warnings, but when someone tries to print he stays abou 3-5 minutes waiting for the printer to print, meanwhile it is almost imposible to work an these winXP computers becouse processor useage is about 50-60% and network useage is 100%. MS Offise opens any document extremly slow if this network printer is set to default. On win98 stations thinks are a little bit better, but sometimes appears the same problem even it is disappearing after a short period of time.

Excuse me if my english is not the best, it is not my native language ...