Dense Memory Cluster (DMC)
The DMC at the Alabama Supercomputer Center has 1256 CPU cores and 6176 gigabytes of distributed memory. Each compute node has a local disk (885 gigabytes of which are accessible as /tmp). Also attached to the DMC is a high performance Panasas file server, which has 15 terabytes of high performance storage accessible as /scratch from each node. Home directories as well as third party applications use the NFS Filesystem and share 4 terabytes of Fiber Channel RAID storage.
The machine is physically configured as a set of 8 CPU core SMP boards. Sixty of the nodes have 64 GB of memory. Twenty nodes have 3.0 GHz dual-core AMD Opteron processors. Forty nodes have 2.3 GHz quad-core AMD Opterons. Ninety-six nodes have 2.26 GHz Intel quad-core Nehalem processors. The SPECfp benchmark for the 2.3 GHz third generation quad-core Opterons is nearly identical to that of the second generation 3.0 GHz dual-core chips. The Nehalem chips are about twice as powerful. Each processor has a floating point benchmark (SPECFP) of 2117 or 4234 for the Nehalem processors.
The DMC has eight GPU (Graphic Processing Unit) chips. These
are arranged in two Tesla S1070 units. These multicore chips
are similar to those in video cards, but are installed as math
coprocessors. This can give significant performance advantages
for software that has been adapted to use these processors.
Thus the processing capacity of the DMC cluster is:
Conventional processing capacity - 5.9 TFLOPs
Single precision GPU capacity - 8.3 TFLOPs
Double precision GPU capacity - 0.7 TFLOPs