Graphical representation of scalability

OS and hardware description

Windows Compute Cluster Server located at the Microsoft Enterprise Engineering Center. Cluster consists of 64 HP BL465c blades , each blade contains 2 Dual-Core Low Power AMD Opteron 2216 HE 2.4 GHz  Processors.  Each blade contains 8 GB EEC DDR 667 MHz of memory.  The interconnect is the 4x DDR IB Switch Module and the IB NIC in each blade is a single-port 4X DDR InfiniBand ® PCI-Express Mezzanine adapter   This all connects to two Voltaire ISR 9024 switches. OS version is Windows Server 2003 R2 64-bit SP2, CCP version 1.0

Test 1, single-point direct DFT (B3LYP) energy plus gradient for medium-size system (623 basis functions). View image

Test 3, single-point direct MP2 energy for medium-size system (623 basis functions, the same system as one used for Test 1). View image

Test 5, single-point direct CASSCF(12,12) for medium-size system (retinal molecule, cc-pVDZ, 565 Cartesian basis functions) using ALDET code. View image

Test 6, single-point direct CIS energy plus gradient of first excited state of medium-size system (porphyrin molecule, cc-pVTZ (aug-cc on Nitrogens), 1130 Cartesian basis functions, D_2h group). View image

All tests were run in standard parallel mode using dynamic load balancing over p2p interface, with four processes per each four-core node. Wall clock times are given on master node in seconds. Test 5 is the most communication intensive and would scale better for larger job. For these tests, the most commonly used MPI calls are MPI_Allreduce and MPI_Bcast.