Want to maximize your IBM POWER 8 hardware investment? You will need the latest XL C/C++ V13.1.1 compiler to fully exploit the POWER 8 hardware capabilities and take advantage of the compiler's industry-leading advanced optimization technology. This demo shows how the suggested optimization levels (-O2 -qipa, -O3, -O3 -qhot) provided by the XL C/C++ compiler can gradually get the best performance for your workload/application. The demo also shows the resulting execution speed comparison between XL C/C++ and the GCC compiler. Two typical benchmarks in SPEC2006 are used for this demo (namd from FP and libquantum from INT).