I don't own the AsRock Extreme9 but the Extreme6. Buying memory for these AsRock boards is very tricky due to the AMD memory controler and AsRock bugged BIOS.
If you're going to have a memory configuration where you use all memory banks, you must take the following into consideration:
http://support.amd.com/PublishingImages/Support/CPU-DDR3/memory-table.png
1.When installing modules of memory of differing speed grades or brand, the memory will always run at the speed of the slowest module installed.
2. The amount of populated memory slots can affect the achievable final memory running speed.
3. Memory design in Single or Dual rank can effect memory speed. Dual rank memory will run slower than a Single Rank memory of equal quality,
4. AsRock BIOS is bugged, If you have memory a SPD profiler with speed higher than maximum memory speed supported by the CPU controller, the AsRock BIOS is going to set that speed. You computer might not boot.
In my personal case, I have 32GB of RAM of 1866Mhz memory - all slot are populated. My memory RAM is Dual Rank which means the controller doesn't officially support speeds higher than 1333MHz. The Asrock 1.40 bios (and all before this one) sets the ram speed to what the SPD tells, which is 1866, It's an unwanted overclock of ~40%.As you can image, the computer doesn't do anything... not even beep.
The Asrock overclock crash guard that supposedly sets a "good" bootable profile picks the same configuration which means that the computer isn't bootable - or, in layman terms, the guard feature doesn't work.
To overcome this, I have to remove all DIMMS but one, set the memory speeds
manually and then populate the remaining slots. If I turn of the computer without proper shutdown the BIOS thinks I have an unstable overclock and sets the "standard/default/good" settings. Obviously, those settings don't work. I have to open the computer remove 3/4 of the memory and set the speed manually again.
I've contact Asrock tech support, which claimed this is AMD fault (it's constraint, not a error) and when they acknowledge the problems (after several emails), provided a "custom" build just for me, supposedly compatible with my configuration - but who knows what was in that bios config.It seems that Asrock engineers can't figure out an algorith that fits all basic rules - set the most compatible configuration. When asked to publicly release the fix they refused.
Long story short, my advise is to avoid Asrock if you find a similar product from another brand. Buy Asrock if you're sure you won't need the tech support.
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