Runtime performance of R and McKmeans on the microarray data. Benchmark results for the artificial microarray data set with 50000 (panel A) and 100000 (panel B) genes, 200/500 arrays, and 10/20 clusters comparing the runtime of k-means R, and McKmeans. Each box summarizes the results from 10 repeated clusterings. Panel C shows the runtime for clustering genes (22277) from 465 cell lines of Smirnov et al. . The parallelization leads to a runtime improvement by a factor of 10.