I am running 16GB of F4-3200C14D-16GTZR in 2x8 and it even runs at very tight timings with 3333 MHz.
It's Samsung B-Die and the XMP profile works as do many of Stiltz' profiles.
Do you think I would be able to double my ram and occupy the two empty slots with another identical F4-3200C14D-16GTZR kit?
I realize I might have to back the speed down a bit, but I'm hoping that at least 3200 MHz will work.
I couldn't get 4X8 to run stable even at 3200. I gave up and reduced to 2X8. I currently run at 3466. I have had quite a bit of experience with Ryzen memory OCing. I owned the CH6 more or less since launch. I tried all the usuals with no success in the 4X8 department. I will try again on the next bios revisions for the CH7.
On a side note. It isn't a good idea to add a second set of memory stick. When you buy 4 sticks of memory as quad channel, you are buying memory that has been verified to work as a batch together. When you buy memory in separate intervals, you stand a chance of finding memory with incompatible timings. Some memory even retains the same vendor code, but it produced at a totally different facility due to production volume changes etc.
I'm running 4x8GB config. It is not factory matched quad - just two sets of trident Z 3200@14 kits (it just happened they are from same batch - they have sequential serial numbers). ……………….
So TL;DR; version.
1) possible but absolutely not guaranteed. Either you have luck of not.
2) manual settings necessary - not only voltages, timings and procODT but RTT, CAD bus, off-center termination voltage also helps as well as correct VRM settings
3) don't treat DRAM calculator as absolute solution - it is pretty good as starting point but for your own chip you may need to tweak values from it
You bought some memory at two different points in time and they have sequential serial numbers?