Are you sure your Fabric is completely stable at 1900+? - may be worth checking that first - Loosen you timings to something silly, change the memory to run at 3200 (when I tested my Fabric I gave my ram 1.4v to be sure). Run several tests to ensure that you are not seeing WHEA errors.
With Dual rank, from what I gather - I do not have these yet (thinking about getting me some), you will need more SOC voltage to clock as there is more demand on the controller. This is turn will drive your VIOD voltage, within 50mv of SOC. SOC up to 1.2v I hear is safe too. VCCD for me I needed 950mv but the range here is 850 to 950.
Thinking about it, I would probably take this approach:
1) Set SOC to 1.2v, set VIOD to 1.15v, set VCCD to .950, set RAM to 1.4v
2) Set RAM to 3200 and loose timings.
3) Set IF to 1900 and test
4) If good, raise if a notch at a time - test. Continue till you start seeing WHEA or crashing (WHEA first I'd expect).
5) Once max stable IF, start to lower SOC volts and VIOD (within 50mv of SOC) until you fail tests\WHEA or fail to boot. Find the voltages that your SOC are happy with at a given IF.
6) Once IF\SOC volts are found, I'd set the RAM v to 1.5 (or less if you are not happy), stick a fan blowing at them and start to to increase ram speed. The safe bet is a one stage increase at a time, testing as you go but you may want to jump boundaries..
7) Once your IF\RAM are at the speeds you are happy with start to lower your Primary timings and test as you go.
8) Once your primaries are set, look at the others.
At 7 and 8, RAM volts should determine what your sticks are happy with. Remember though, you have Dual range in these 32g kits so your mileage may very.
@MrPils has written several 'how to' within this thread. His approach will probably get you what you want from your sticks. I'd suggest you look back to page 47 and read his comments, this single page helped me the most to tune (semi - I have more in my sticks if I give them more that 1.44v).
Hope this helps - I am new to this though so hope I've not given you a bum steer.
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