I just put together a K8NSC-939 board with an X2 4400+ and 4x 512mb PQI dimms. With all four dimms in, or with slot 1 and 2 populated, I get one long beep, and no post. With slots 1 and 3 populated, it will post, but then I get the message "Memory not optimized", and it says to check the manual (which has nothing about it that I can see. The CPU is a retail version, the ram is "MD4412UOE" PC3200. I have upgraded the bios to F6 as well. Any suggestions where to look for a solution? I have googled the heck out of it, and have not found much good information. I get this problem with any of the ram modules, and with 2 older sticks of Crucial PC3200 512mb sticks.