if you check the asus ftp site, you'll notice that their is a 1004 bios for the a7n8x v1.xx. It includes 200MHz bus support for the new 3200+.
I just upgraded this morning (board rev 1.04), and the bios seems fine although I don't have a 3200+ processor to try out the new bus speed.
After reading a few boards, it looks like the bios probably increases stability for the chipset; Nvidia mentioned that the new bios reduces noise on the board required for higher speed operation.
ftp://ftp.asus.com.tw/pub/ASUS/mb/socka/nforce2