Did you try clearing the CMOS and just one stick of RAM?

There is a review at newegg that had the same problem:
"Other Thoughts: Bought this with 4GB of Corsair TWIN2X2048-6400C4. Everything was great until about a minute in the machine started rebooting continiously and refused to POST. After much hair pulling, turns out the solution was to take out all but one stick so the machine would run the memory single chanel, then I could update to F6 bios, now everything works fine with 4GB in dual channel."