Abstract　 　 
New powerful supercomputers have been built using graphical processing units (GPU) for general purpose computing. China has obtained top ranks in the list of the fastest super- computers in the world with a GPU based system. The research of Chinese Academy of Sciences and NAOC in Beijing with such GPU clusters will be reviewed, present and future applications in computer simulation and data processing discussed. We present particle- and mesh-based algorithms for astrophysics using hundreds to thousands of GPUs for one single application run in a parallel message passing environment, some with detailed timing models. Future perspectives for GPU and FPGA accelerated computing will be discussed and international collaboration in the ICCS (International Center for Computational Science). GPU and other 'green' supercomputing hardware is a stepping stone on the path to reach Exascale supercomputing. An application to astrophysical Computer Simulations of Dense Star Clusters in Galactic Nuclei with Supermassive Black Holes is presented. We use large high- accuracy direct N-body simulations with Hermite scheme and block-time steps, parallelised across a large number of nodes on the large scale and across many GPU thread processors on each node on the small scale. We reach a sustained performance of more than 350 Tflop/s for a science run on 1600 Fermi C2050 GPUs; a performance model is presented and studies for the largest GPU clusters in China with up to Petaflop/s performance and 7000 Fermi GPU cards. Our simulation proceeds to the complete relativistic merger of the black holes, including Post- Newtonian corrections to gravitational forces and the relevance of the results for the cosmological background of gravitational radiation is briefly touched. We discuss the relevance of this for pulsar timing bands and for frequency bands of new space based gravitational wave missions in China and Europe.

P.S.：We offer interested teams from China and abroad to explore the use of our laohu (tiger) GPU supercomputer at NAOC in Beijing. After the colloquium talk I can give a short technical hands-on introduction how to use it. And there is an invitation, especially for young students and postdocs from China, to come to Beijing and attend the 3rd ICCS school and workshop March 26-30, 2012 at NAOC, with hands-on lectures and science talks on how to use this computer. See http://ilibrary.las.ac.cn/web/silkroad/3rd-iccs-workshop/school