Some of you might find this a handy tool
it sets the process priority ie it allows u to control how much
of your cpu is used by a specific process. U can of course use
the taskmanager to do this, but this tool allows u to do it via cmd line.
U could use this to set priority of mdcrack to low for eg, thus wouldnt
interfere with the rest of the system.
http://gilchrist.ca/jeff/SetPriority/