RISC chips understand fewer, but more generalized, instructions than their CISC counterparts. RISC is currently recognized as the correct way to do good CPUs by everyone but Intel, it seems.
While RISC chips have to process more instructions than a CISC chip would need to do the same thing, they can process them faster because of smaller lookup tables. RISC chips include: PowerPC, Alpha, SPARC, PA-RISC, MIPS.