Multicore Processor: Number of Threads

Hello guys! I want to improve RapidMiner 7 hardware performance.

My system: Intel Core i7-2600 (4 physical cores = 8 hyper-threading cores), Win 7 Ultimate 64 bit, 8 GB RAM.

Should I set the Number of Threads option in RapidMiner to 8 for better performance or keep 0 (default)?

Thanks!