Application performance on the UK's new HECToR service

HECToR is the UK’s new high-end computing resource available for research funded by the UK Research Councils. The HECToR Cray XT4 system began user service in October 2007 and comprises 5,564 dual core 2.8GHz AMD Opteron processors. The results of running a number of synthetic benchmarks and popular application codes which are used by the UK academic community are presented. The synthetic benchmarks include STREAMS and MPI benchmarks. The application benchmarks include fluid dynamics, molecular dynamics, fusion, materials science and environmental science codes. The results are compared with those obtained on the UK’s HPCx service which comprises 160 IBM e-Server p575 16way SMP nodes each containing 8 dual core 1.5GHz IBM Power5 64-bit RISC chips. Where appropriate, results are also included from the HECToR Test and Development system which has a different memory structure from the main system. It is found that there is not much difference between the systems in terms of comparing similar numbers of processing cores, but HECToR is a much larger system with many more cores and a more scalable interconnect. Memory bandwidth is seen to be a bottleneck for certain applications on both systems, with HECToR more seriously affected.