Benchmarking a Reduction in # of CPUS

Dear Oracle Support Community:

Is it possible to simulate a reduction in number of CPUS in an Oracle 10g
environment?  We have an ODS system that performs a nightly ETL batch run.
It runs on SunOS 5.8 and has 10-2Ghz cpus and 40Gb memory. We plan to move
to new hardware in the near future and need to simulate a reduction in cpus
and memory.

Our current daytime cpu usage is < 10%.  Our batch usage is around 30%,
but peaks at >90% for several of the programs. We have surplus time and
can easily extend the batch wall time by 25%.  

We want to limit Oracle to fewer cpus without turning off the cpus via the