Windows Media Encoder x64 Edition
Windows Media Encoder is one of the few popular video encoding tools that uses four threads to take advantage of quad-core systems, and it comes in a 64-bit version. For this test, I asked Windows Media Encoder to transcode a 153MB 1080-line widescreen video into a 720-line WMV using its built-in DVD/Hardware profile. Because the default "High definition quality audio" codec threw some errors in Windows Vista, I instead used the "Multichannel audio" codec. Both audio codecs have a variable bitrate peak of 192Kbps.

The fastest CPU finishes encoding this clip in less than half the time it takes the slowest one to finish. Broken record here, but look, the Core 2s are faster than the Athlon 64s!

LAME MP3 encoding
LAME MT is a multithreaded version of the LAME MP3 encoder. LAME MT was created as a demonstration of the benefits of multithreading specifically on a Hyper-Threaded CPU like the Pentium 4. Of course, multithreading works even better on multi-core processors. You can download a paper (in Word format) describing the programming effort.

Rather than run multiple parallel threads, LAME MT runs the MP3 encoder's psycho-acoustic analysis function on a separate thread from the rest of the encoder using simple linear pipelining. That is, the psycho-acoustic analysis happens one frame ahead of everything else, and its results are buffered for later use by the second thread. That means this test won't really use more than two CPU cores.

We have results for two different 64-bit versions of LAME MT from different compilers, one from Microsoft and one from Intel, doing two different types of encoding, variable bit rate and constant bit rate. We are encoding a massive 10-minute, 6-second 101MB WAV file here, as we have done in many of our previous CPU reviews.

At best, you can expect to shave about 10 seconds per song (and this is a long song) off of LAME encoding jobs by choosing a Core 2 Extreme X6800 over a Core 2 Duo E6300. Going quad-core won't get you anything here (except perhaps the ability to run two or three encoding tasks simultaneously). The Core 2 Extreme X6800 takes the top spot throughout our LAME tests, but the competitive landscape shifts quite a bit depending on the encode type and compiler used.