That's the newer P8 type for use on both older and the latest boards out. You often see one part with a cover on it and simply use the other. The main 24pin connector usually sees a smaller 4pin pop off section for the old 20pin mains seen on old Socket A, 754 AMD boards or pre Pentium Intel models.
The introduction of the P4 line saw the extra power feed introduced there. The latest quad core boards are now seeing 8pin sockets at this time over the typical 4pin common on both Intel and AMD boards that followed being 939, AMD2(940), AM3 for AMD, and Socket 478, 775 for Intel.