Is it possible to make the process of thinking that the processor is slower than it actually is?
No. You can however specify the process Affinity for limiting the number of cores its able to utilize?
For example; If you limited the process to 1 core on a quad-core (4) system the process would only be able to utilize 25% of the processor.
2 core processor = 50% utilization per core
4 core processor = 25% utilization per core
6 core processor = 16.6% utilization per core
8 core processor = 12.5% utilization per core
10 core processor = 10% utilization per core
12 core processor = 8.3% utilization per core
If you have 4 cores - each one has a maximum 25% utilization of 100% - If you limit the process to two cores it can only utilize 50% at maximum.
If you have 12 cores - each one has a maximum 8.3% utilization of 100% - If you limit the process to two cores it can only utilize 16.6% at maximum.
Hopefully that makes sense?