And then..
Good boy!!! You finally figured it out

.
2 reasons why I say bios flash, although I wish you figured it out as well but :bleh:
#1. The 1st fix mentioned under 0512 :
What's the relevance? The ICs. Corsair rams uses ICs from elpida, Promos, hynix and also- Hello hello! Samsung! Most likely he might have the corsair rams with the same/relabelled samsung ICs.
#2. Self explanatory:
Maybe the service tested the system with another graphic card, most likely anything but ati 5850 and 5870. Could you always do the "Gadha majdoori" and waste 7 business day's time by RMAing the card, possibly functioning from their end and returning with an "ok tested" tag to facepalm yourselves to glory if and when you try the steps I told or try the steps I told which would take barely an hour's time?
Anyone who has the ups and downs with asus boards will know the anguish as far as ram compatibility is concerned. Flash the BIOS, if it doesn't work, reduce the ram frequency till asus releases a better bios.