Looks like the Gigabyte 6-QUAD GA-P35T-DQ6 does pretty well with audio and video encoding. Most of this can be attributed to the 1333MHz FSB and how well Intel optimized the data throughput for the P35 chipset. Simply put, the P35 is a wickedly fast chipset.
As for that one odd figure for the Gigabyte P35-DS3R in Lame MP3 encoding, that was another odd testing error.