How to tell which programs make use of six cores

[Jskid]

When deciding to get a 4 core or 6 core CPU I red that only certain programs use the extra 2 cores. Is there a list of these programs? Would the OS make use of the 2 cores so that the computer would start up or shutdown faster? Or is the startup/shutdown time not a function of the CPU and has more determined by the hard drive.

 

[Tmagic650]

If you use Windows 7 there are CPU Gadgets that will show you how many cores are being accessed at a given time. My Intel i5 CPU has 2 cores and 4 threads

 

[red1776]

or you can use task manager like I do. If one of the programs in question is Photoshop CS5 btw, it does as well as parallel processing.