Is instruction set and CPU architecture the same thing?
The instruction set is what instructions the CPU can handle. An ISA includes a specification of the set of opcodes (machine language), and the native commands implemented by a particular processor. Instruction set architecture is distinguished from the microarchitecture (CPU architecture), which is the set of processor design techniques used to implement the instruction set. Computers with different microarchitectures can share a common instruction set. For example, the Intel Pentium and the AMD Athlon implement nearly identical versions of the x86 instruction set, but have radically different internal designs.
