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By Uwe Harms, Harms-Supercomputing-Consulting -- In this article an old friend from Munich, Uwe Harms, examines the specifications and overall performance capabilities of NEC's new SX-6 supercomputer. Also discussed is the adoption of the new system by DKRZ (Deutschen Klimarechenzentrum - German Climate Research Center) and the alliance between Cray Inc., and NEC. The development of this system is evolutionary, as it based - as the predecessors SX-2 to SX-5 - on the principle of vector processing. The same arithmetic operations are processed on large columns of numbers. This results in a high performance. This is demonstrated by the Top500 and the Linpack benchmark. In the list this class of computers exceeds sometimes 90% of the peak performance in the Linpack, while massively parallel systems only gain 50%. The single SX-6 processor has the same peak performance as the SX-5 but some internal improvements result in better application performance. The clock rate has been reduced from 4 to 2 Nanoseconds and the number of arithmetic pipes went down to 16 (8 adding, 8 multiplying) from 32 of the SX-5. This improves the performance in applications with shorter vectors. Another effect of the one-chip realization and modern CMOS technology is the reduction of space and power consumption - down by 80%. Instead of using 50 square meters, a new 16 CPU machine needs 3 square meters. The entry level model with two processors and 64 GB memory will cost below one million dollars, but as in this high-end market, the prize is a matter of negotiation. NEC says that the SX-6 has a price-performance relationship of a factor of four better than that of the SX-5. NEC puts up to 8 processors with 64 GB memory within a node chassis. These nodes can be connected via the NEC proprietary Internode Crossbar Switch. In total up to 28 nodes (1024 CPUs) with an aggregated memory of 8 TB can be connected. The peak performance will be 8 TeraFlop/s. Some computers will be delivered this year, but beginning with the first quarter of 2002 there will be a broad delivery. A specialty of vector supercomputers is the high bandwidth of memory access. Therefore they do not use caches but only vector and scalar registers. The SX-6 with 8 processors has a peak transfer rate to the memory of 256 GByte/s, this means 32 GByte/s per processors. The internode connection has a high transfer rate, in the biggest system it sums up to 1 TeraByte/s between the 128 nodes. NEC expects to sell about 300 computers within the next three years. Their target markets are the environment/climate research/meteorology, automotive, aerospace industry as well as Research Institutes. Actually NEC has installed 300 SX-systems worldwide, about 70 of which are in Europe. The operating system SUPER-UX, a Unix derivative, refined throughout the years is a stable system in the computer centers. In co-operation with the middleware it supports efficiently the multi node operation.The system offers the user a single system image. Additionally NEC offers important development tools and production environments like MPI, OpenMP, PSUITE and Vampir from Pallas, Germany. During the press meeting NEC announced that it has sold some SX-6 computers. The first and most important system will be installed by the DKRZ (Deutschen Klimarechenzentrum - German Climate Research Center) in Hamburg. For a long time the center had to use the 1995 installed Cray C90 with 16 processors, 16 GFlop/s. Now the DKRK can acquire a NEC SX-6. First for a short-time solution, DKRZ will use two SX-4. The Cray will be switched off by end of October 2001. Next year in February DKRZ installs 8 NEC SX-6 nodes, 64 processors. In August 2002 another 8 nodes will be added. The last step will be realized in April 2003. Approximately 192 CPUs, 1.5 TByte memory and 1.5 TeraFlop/s peak performance are available at DKRZ. In typical climate programs DKRZ expects a sustained performance of 500 GFlop/s and a performance improvement of a factor of 100 compared with the Cray C90. The disc capacity will grow to more than 60 TeraByte and more than 3.4 PetaByte tape memory archive. From an observer's perspective, who is in the field for nearly 30 years, the behavior of Cray is interesting. In spring 1996 the trade commission put an anti-dumping duty og 450% on NEC vector supercomputers, based on an accusation from Cray Research. This year NEC and Cray Inc. signed an OEM agreement and this trade barrier was thrown away. Now Cray Inc. sells the NEC vector computers in North America, named Cray SX-6. This was probably the result of the climate research report from the end of last year to the White House that the US is falling behind the rest of the world's research in this area. Cray will announce its own Cray SV2 vector processor for the second part of 2002, it will lie in the same performance range as the SX-6. Let's see what will happen? Supercomputing was always a field of interesting events and changes. ---------- Uwe Harms is President of Harms-Supercomputer-Consulting. Supercomputing Online thanks him for his time and insights. ----------