These tests were done on servers with 2GB, 4GB, 6GB and 8GB memory and they used various system load levels to compare the power efficiency of chips from both processor makers.
According to NNA AMD Opteron server processors were in some cases 9.2 to 23.1 percent more efficient while Intel's Xeon chips lagged behind with numbers between 2.4 and 11.7 percent in some tests.
The firm also found that Intel's power efficiency drops as memory sizes increase, while the opposite is true for AMD Opteron systems.
However, The Inq writes Intel wasn't really happy with these results and points out that NNA failed to include Intel's latest chips in the test:
An Intel representative commented: "The report doesn't measure our latest Xeons, or quad cores. We have 2GHz quad cores in the market at 50 watts, 12.5 per core! The report ignores performance, in that you'd use less Intel servers to get the same job done, meaning less electricity is needed.
"We stand behind all of our energy efficient claims, period. For those IT managers who don't do their own in-house testing, we recommend that each look at the 100s of independently verified benchmarks and reviews that exist for the most credible assessment."