They rank on top in the benchmark tests:
http://www.cpubenchmark.net/Ranked by group, the Intel Core2 Duos and Xeons are the highest performers, with the Netburst family edged out by AMD's offerings. The Celerons and Semprons are at the bottom. Note that Xeons are named confusingly because there are both Netburst and Core2 versions, and they are nowhere near each other in performance. The advent of multiple cores has also made ranking a little more difficult, since two slow cores can theoretically outperform a fast single core, in certain applications.
