In its latest round of power-efficiency tests pitting the AMD Opteron against the Intel Xeon, independent consulting firm Neal Nelson and Associates found that AMD's offering outperformed Intel's in 36 of 57 cases. Factors such as memory size, transaction type, and transcation loads made for notable and interesting differentiators. In its latest round of power-efficiency tests pitting the AMD Opteron against the Intel Xeon, independent consulting firm Neal Nelson and Associates found that AMD’s offering outperformed Intel’s in 36 of 57 cases. The results are by no means cut and dry. While the AMD appears to once again have an edge in terms of raw power effienecy, factors such as memory size, transaction type, and transcation loads made for notable and interesting differentiators. Nelson performed this gauntlet of tests on servers — one equipped with the Opteron 2222 and the other with the Xeon (Woodcrest) 5160 — configured with two, four, six, and eight gigabytes of main memory at various transaction-processing load levels. Overall, Nelson found that for certain configurations and at certain load levels, the Intel Xeon based server was 2.4 to 11.7 percent more power efficient while in other cases the AMD Opteron based server was 9.2 to 23.1 percent more power efficient. Memory once again proved an important variable. In general, larger main memory sizes resulted in higher transaction throughput and higher power efficiency. Further, in cases where Intel outperformed AMD in power efficiency, the servers were configured with smaller larger memory sizes. “There was a visible trend that as the memory size increased that there was an increasing shift of power-efficiency toward the Opteron,” Nelson notes the white paper outlining his testing.Importantly, Nelson discovered differences in power-performance depending on what type of work the servers were doing. At the maximum throughput, based on transactions per watt hour, the Intel system delivered better power-efficiency by 5.0 to 5.5 percent for calculation intensive workloads. For disk I/O intensive workloads, AMD delivered better power efficiency by 18.4 to 18.6 percent. In addition, when the systems were idle and waiting for transactions to process, the AMD server was 30.4 to 53.1 percent more power efficient.He put the machines through two different tests. One employed the Neal Nelson Transaction Benchmark, in which simulated Web clients present transaction requests to the server. As soon as the server responds to a request, the client submits a new request.In the second test, employing the Neal Nelson Power-Efficiency Benchmark, he presented the servers with a set number of transactions, then measured the power expended for each transaction arrival rate. For the loads, he simulated over-the-Web credit card transactions on the servers from RTE (Remote Terminal Emulator) nodes to the machines, which were running Apache2.You can read the white paper outlining the testing and results here on the Neal Nelson and Associates Web site. Technology Industry