nice runs utility at an altered scheduling priority. If an increment is
given, it is used; otherwise an increment of 10 is assumed. The superus-
er can run utilities with priorities higher than normal by using a nega-
tive increment. The priority can be adjusted over a range of -20 (the
highest) to 20 (the lowest).
The options are as follows:
A positive or negative decimal integer used to modify the system
scheduling priority of utility.
The nice utility shall exit with one of the following values:
1-125 An error occurred.
126 The utility was found but could not be invoked.
127 The utility could not be found.
Otherwise, the exit status of nice shall be that of utility.
This is from "man nice" on a BSD box. You can mess with the nice and give it a higher priority.