Utilizing the core-avx2 CPU optimizations offered by the GCC 4.8 compiler can provide real benefits for the Intel Core i7 4770K processor and other new "Haswell" CPUs. For some computational workloads, the new Haswell instruction set extensions can offer tremendous speed-ups compared to what's offered by the previous-generation Ivy Bridge CPUs.

With our source-based benchmarks to date of Haswell, we have been using the -march=native compiler flag that effectively means -march=core-avx2 but we haven't looked specifically at the benefits provided by Haswell CPUs introducing support for AVX2, FMA, BMI, and BMI2. This is also particularly interesting since on the Windows side, most of the benchmarking that happens at the other review sites is done using generic pre-compiled binaries rather than building from source with optimizations for a given architecture.