The SB600 has worked fine for quite a while. The problems seem to be more related to loading Vista on the 790FX chipsets. There were a couple workarounds, but they weren't very good. I'll try to look up the article and post it. The proposed solution was the SB700, but its possible that there is some other design problem as well. The tested motherboards were from ASUS, Gigabyte, and MSI, so it seems to be more than a single company making an error, pointing to a systemwide fault.
I found the review that details the SB600 problems:
http://techreport.com/articles.x/13832
From the article, though the whole aticle should be read for clarification:
AHCI Issues
A documented compatibility problem between Windows Vista and the 790FX chipset's SB600 south bridge component currently complicates running drives in AHCI mode.
That's if it works at all. One can install Vista by putting the SATA controller into IDE mode, but AHCI mode is necessary to take advantage of Native Command Queing and SATA device hot swapping, so its not a trivial capability to loose.