I had some wave files that I wanted to encode to mp3. I wrote a small parallel processing framework for this job. It executes parallel jobs so I can benefit from the 4 cores + 4 virtual cores of my new Core 7i 920 processor.
The framework is based on some shell scripts running on Linux (or probably any other unix) and Lame.
I wanted to test how much impact hyperthreading has on parallel performance. Hyperthreading has a bit of a bad reputation, dating back from the P4 erra. Lots of 'hype' but no significant performance gain.
I ran some test with hyperthreading enabled and disabled (within the bios).
In this test I used 16 wav files and encoded them to mp3 with Lame under Linux. The data in the table are raw measurements.
As you can see, the benefit of HT is there and can improve processing speed with up to 24 percent.
As more threads are run simultaneously, processing speed is significantly improved comparted to non-HT.