Getting CPU type and number of processors

What’s the CPU type of my Macintosh?

For a generic answer, use System Profiler: Hold down the Option key while opening the Apple menu and select System Profiler ….

A more specific answer is available on the command line. Type

sysctl -n machdep.cpu.brand_string

for the actual name of the CPU built into your Intel-based Macintosh. On older PowerPC Macs, the hostinfo command will return the CPU name.

How can I find out how many processors the Mac OS X box I’m currently logged in has?

The command sysctl hw.ncpu will help you out.