When it came to 2D performance as measured by the Java 2D Microbenchmark profile that was contributed to the Phoronix Test Suite by Sun Microsystems, Mac OS X had delivered faster performance. Mac OS X 10.5.6 was 275% faster than Ubuntu 9.04 at 2D text rendering.
While turning away from the graphics tests, OS X continued to perform stronger even at MP3 encoding. Mac OS X 10.5.6 was nearly 10% faster than Ubuntu 9.04 when it came to encoding a WAV to MP3 file using LAME.
By a larger margin, when changing a WAV file to Ogg using the Ogg encoding software, OS X 10.5.6 remained faster. There was a noticeable difference in performance, and yes, the Phoronix Test Suite does carry out tests multiple times to ensure statistical significance.