NEGOTIATOR_POST_JOB_RANK can help here. See:
http://www.cs.wisc.edu/condor/manual/v7.4/3_3Configuration.html#20450
I use:
## Break ties by looking for machines that have Idle longer than others
## and use them first. Also try and use faster machines before slower
## machines and assign jobs to separate machines before we start putting
## two jobs on a machine.
ALTERA_NEGOTIATOR_POST_JOB_RANK = (((Activity =?= 'Owner') * (State =?= 'Idle')) * 1000000000) + ((Activity =?= 'Unclaimed') * 100000000) + (KFlops * 0.001) - (SlotID * 10)
- Ian