Do the other processes do much disk IO?  Maybe it's your disk that can't 
keep up.  Nice doesn't have much effect when a process uses up all the 
disk IO.

If you have multiple disks, you could try moving files around such that 
the files being served by smb are on a different disk that the others 
(and also a different disk than the system install)

Dan


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Daniel Armbrust
Biomedical Informatics
Mayo Clinic Rochester
daniel.armbrust(at)mayo.edu
http://informatics.mayo.edu/