i think the difference is one supports the nvidia nforce2 (a7n8x) and the other has a via chipset (a7v8x)
im not sure of the difference between the two, but the a7v600 is also a via based board (with the 600 chipset)
there is a link here:
http://www.digit-life.com/articles2/...-axp3200+.html
that compares an athlon 3200+ xp running both a7n8x and a7v600 boards, with a p4 3.2ghz running two different motherboards also.
anyway, the test (although i believe the a7v8x is faster than the a7v600) clearly shows that the nvidia based board (a7n8x) is considerably quicker than the via based board.
hope that helps
alex