CHIPMAKER Intel might have been banging on about the energy efficiency of its Xeon Phi accelerator but a consumer Core i5 cluster is the most energy efficient x86 supercomputer on the Top 500 list.
During Intel's Xeon Phi announcement, the firm claimed its experimental Discovery cluster was the second in energy efficiency after the much more mature IBM Bluegene clusters. However looking through the full Top 500 list released on Monday, Intel's Discovery cluster isn't second, or even third, and in fact a cluster consisting of Core i5 processors delivers more than 17 per cent higher MFLOPS/W than the Discovery cluster.
Nagasaki University's DEGIMA cluster managed to rack up 1,378.32 MFLOPS/W while Intel's Discovery cluster featuring Xeon Phi accelerators delivered 1176.59 MFLOPS/W, putting it two places down on the list. The DEGIMA cluster is made largely from off-the-shelf components, featuring 2,475 quad-core Intel Core i5 processors running at 2.93GHz and using ATI Radeon GPUs. DEGIMA employs industry standard Infiniband QDR interconnects to link all those nodes, creating a self-made cluster that is more energy efficient than clusters made by high performance computing veterans such as Bull, Fujitsu, HP and SGI.
Not only does Nagasaki University's cluster show up Intel Xeon E5 processors and the Intel Xeon Phi, it also scores an unlikely win for AMD in a roundabout way. While information on what AMD GPUs DEGIMA uses is scant, it does show that if AMD got serious with Linux OpenCL support it could be onto a winner.
Intel's Discovery cluster was also beaten by a Bull cluster installed in the Barcelona Supercomputing Centre that uses previous generation Intel Xeon chips and Nvidia Tesla M2090 boards. Intel's claims of Xeon Phi powering the second most power efficient cluster might be in tatters, but the firm can rightly claim that its Discovery cluster is still a work in progress and there could well be improvements that help it overcome its rivals and its own Core i5 processor.
However Intel's in-house battle with its own chips is something of a sideshow, as IBM's Bluegene clusters powered by the firm's own Power BCQ processors account for the top 19 places on the Top 500 list in terms of energy efficiency. IBM's two most energy efficient clusters both sporting 8,192 Power BCQ cores reported 2,101.39 MFLOPS/W, over twice the energy efficiency score of Intel's Discovery cluster. µ
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