Independent tests conducted by Neal Nelson & Associates, an independent computer performance consulting firm, have found that AMD's Opteron-based servers deliver better power efficiency than Intel Xeon-based counterparts.
A quote from the laboratory test report reads:
The tests were performed on servers configured with 2, 4, 6, and 8 gigabytes of main memory at various transaction processing load levels. The results show 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. 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.
AMD's Opteron-based servers were found to provide more power efficiency with increasing memory size. Also, the tests concluded that while Intel's Xeon was more efficient for calculation intensive workloads 5.0 to 5.5 percent, AMD Opterons were more power efficient at I/O intensive operations by 18.4 to 18.6 percent.
An article at EDN quotes that Neal Nelson, the firm's founder, undertook the tests to independently verify Intel CEO Paul Otellini's claim concerning Intel's lead in power efficiency. An Intel representative disputed the report, saying that the test does not consider the performance of Intel's latest Xeons, or quad cores.
Research firm claims AMD beats Intel on power efficiency (The Inquirer)