Points well taken. The motherboard is th K8N Neo2 Platinum with a Athlon 64 3500+ cpu. The memory is Corsair XLS 3200 pro( 4 512 Mb modules). I tried setting it to DDR 400 at 2T timings and the board did not post until I removed 2 dimms. It is kinda mute now because the board was RMA'd due to "chipset not found" at post.
rickcfer
So you've got the K8N Neo2 also - now it makes perfect sense that you were wondering how AT got around the memory timing defaulting to DDR333 WITH ALL SLOTS FILLED, as you said - MSI has this documented in their own manual. Strange.
Anyway, I seemed to recall that when I was running four sticks of Mushkin PC3500 Level II in my board (K8N Neo2 Platinum) I could MANUALLY set max memory speed to 200MHz at 2-2-2-5 and the board would default to 2T Command Rate. So, this afternoon I re-installed another Mushkin PC3500 Level II DualPack (512MBx2) in my machine. I then ran CPU-Z v1.24 and the "Memory and Cache Bandwidth Benchmark" under SANDRA 2004. CPU-Z showed 2048MB in Dual Channel at 2-2-2-5. Strangely, for some reason SANDRA 2004 shows my memory as only 1 Channel of 2x 200MHz (400MHz data rate) in a 4-Way Bank Interleave of all four banks (0, 1, 2, and 3).
I don't know if your new board (assuming you get a "new" board) will be able to run all four sticks at DDR400, which it should (albeit at 2T Command Rate). Mine does as did the AT test board. If not, at least the new board you get should be trouble-free. If you're lucky you may even get a later revision board, which is usually a good thing due to problems found on first revisions of boards being ironed-out in later revisions.
Lastly, as AT stated in their review, all of the 939 boards they tested, if they could even run with all banks filled had to run at 2T Command Rate, which have a significant negative effect on memory benchmarks. My system will freeze on the third run of the Halo timedemo when running 512MBx4 of the PC3500 Level II Mushkin at 2-2-2-5 2T (no OC). I also notice a speed difference when playing online multiplayer Halo, which is why I pulled 1GB of memory out of my machine before. I'm gonna pull it back out again now that I've re-confirmed that my board DOES run 512MBx4 at 200MHz Dual Channel.
Please post back and let me know how it works out with your new board. Good luck.