What is the difference between an execution core and a execution unit in a processor? I know that an ALU or FPU is an execution unit, but what is the difference with a execution core?

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An execution core consists of one or more execution units, a control unit, and various other parts. On modern CPUs, each core typically consists of more than one execution unit. A quad-core CPU has four cores. If it's hyper-threaded, then the execution units in each core can be shared by two threads simultaneously. Execution units perform the actual operations such as branching, mathematical operations, memory operations, and so on. Each core has a control unit which distributions instructions to the various execution units in the core.

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    so regarding his question, is he wrong when he says "I know that an ALU or FPU is an execution core" Where does the ALU and FPU(which the questioner used as examples), fit into the terminology you mention? – barlop Oct 20 '13 at 15:26
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    The term "execution core" is usually used to describe the ALU, FPU, instruction scheduler, registers, and so on, as a unit. The ALU and FPU are execution units (hence the 'U' in their acronyms). – David Schwartz Oct 20 '13 at 15:46
  • I updated the question and fixed the mistake core/unit, for future reference. Thanks again. – Wouter Oct 20 '13 at 18:11

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