Surely, you could get better answers to that by using your web search engine, if you can define your question better. With so many reviews of Intel compilers and benchmark comparisons with various other compilers available on the web, why ask here? With recent Intel compilers and all but the earliest Athlons, the SSE code generation switch has been effective for running on P-III, P4, and Athlon, and older compilers generally can't match that.