We have a dedicated HPC that used for physics analysis, which is a mixture of standard CPUs and GPUs, with ~500 Tb of disk space, and that we also host a Grid Tier-2 site, that is mainly used for the production of ATLAS Monte Carlo data.
GridPP is a collaboration of particle physicists and computer scientists from the UK and CERN. They have built a distributed computing grid across 17 UK institutions, helping to process the data from the world's largest particle accelerator, the Large Hadron Collider, as well as many other EPP experiments. The EPP group at Sussex is part of SouthGrid, the branch of GridPP in the South of England.
You can find out more about High Performance Computing resources at Sussex here.