HECToR[4] (High End Computinging Terascale Resource) is the UK National Supercomputing Service, and consists of Cray XT and X2 hardware. During this project, the Phase 2a (XT4) and Phase 2b (XT6) components of the system were used.
The XT4 consists of 5664 compute nodes, each containing a 2.3 GHz quad-core `Barcelona' AMD Opteron processor and 8 GB of main memory, giving 2 GB per core. The nodes are connected to the Cray High Speed Network by a SeaStar2+ router chip. This gives a peak performance of 208 TF, and the system is ranked 26th in the June 2010 Top 500 list[5]. The system has since been halved in size to make way for the newly-installed XT6 system (Phase 2b).
The XT6 consists of 1856 compute nodes, each containing two 2.1 GHz 12-core `Magny-cours' AMD Opteron processor and 32 GB of main memory, giving 1.33 GB per core. Similarly to the XT4, the nodes are connected to the network via a SeaStar2+ router, although this will be replaced in late 2010 by the upgraded Gemini interconnect. Currently the peak performance is 360 TF, and so the XT6 ranks 16th in the June 2010 Top 500 list.