Lawrence Berkeley National Laboratory's Erich Strohmaier is an internationally known expert in assessing and improving the performance of high performance computing systems. How the system performs over the long haul, rather than its short-term potential, is what matters. And as one of the co-founders of the twice-yearly TOP500 list of the world's most powerful supercomputers, Strohmaier has found that the most important information comes from looking at the changes in the list over time, rather than by just looking at the systems on one list. Strohmaier is the leader of the Future Technologies Group in the Computational Research Division at the U.S. Department of Energy's Berkeley Lab. He is PI for the joint Math-Computer Science Institute CACHE and Deputy-PI in the DEGAS (Dynamic Exascale Global Address Space Programming Environments) project.