I am also using the same board as you have and i have found the onboard sound setup of the board not being so great. Are you having the same problems. If not then what drivers are you using for the same. Also are there any new bios's around. Bloddy pain these days to keep looking for stablity with high end products.
am using an old creative card at the moment but i used onboard for a few weeks and found it ok.. i downloaded the drivers for onboard sound from the asus site it was newer than the ones on my cd but since you got your board recently the contents of the cd may have been updated
bios wise the latest official release is 1009. there are huge number of betas after that and it looks like asus is seriously working in the memory area
i m using bios 1010 beta version 003 so far ok
asus are already working on 1011 without releasing the official 1010.. there are so far 5 releases for 1011 and i would seriously advice you not to touch any of those
are you facing any problems with the board ?