Battlefield 1 runs on the same engine as Battlefront 2 (Frostbite 3 iirc), and it's known for crashing overclocks that are stable elsewhere. I think it uses some sort of AVX instructions but it somehow doesn't pull all the voltage the CPU needs to do so. I've experienced it first-hand with a 6600k and 8700k, so flaky overclocks are prone to fail.
But first, the sanity checks: 70ºC in Prime95 for 1,375Vcore seems too low. I'm guessing you're using the 26.6 version without AVX, you should stress-test with AVX instructions as some games make use of them when available. Based on my own experience, if you pass the standard 10 loops of Intel Burn Test 2.54 in its "High" preset (2048MB of RAM) or "Very High" preset (4096MB), that's the kind of stability you guarantee going through hours of Prime95 (with AVX instructions). You may need to give some more milivolts to Vcore or play with LLC settings. Mind you VID=!Vcore, check CPU-Z or the
Vcore reading from hwinfo64 to properly read the voltage that's coming into the CPU pins.
Second sanity check: I own the ASRock Z370 Extreme4 which should be equivalent to the Taichi in terms of overclocking as both use same layout and VRM; check
https://www.hardwareluxx.de/community/f12/lga-1151-mainboard-vrm-liste-1175784.html#z370). The board sets
VccSA and
VccIO too damn high in Auto settings, and overshooting said voltages hurts stability. Not only it does that, but some brick-head at ASRock felt like when you overclock memory, you need to pull up aswell the
VccST (absolutely WRONG: manually FIX VccST to the default voltage if you're not using LN2, plain simple).
That resulted in some funny voltage readings when I first loaded the XMP of my sticks (4000Mhz CAS19):
-VccSA went from 1.05 to
1.35V ! (Auto)
-VccIO went from 0.95 to
1.30V ! (Auto)
-VccST went from 1.0V to
1.20V ! (Auto)
I know from Skylake that
1.35V in the System Agent is not suitable for 24/7 use, but I tried to run Battlefield just for fun. CPU was running pretty toasty nearing the 70ºC region and it crashed after a few minutes. So after some days of trial and error, I ended up with a rock-solid configuration at 4000Mhz CAS16 1,43Vdram and the following CPU voltages:
-VccSA pulled down from 1.35V(Auto)
to 1.20V (in BIOS), reading 1.216V as average real voltage in hwinfo64.
-VccIO pulled down from 1.30V(Auto)
to 1.15V (in BIOS), reading 1.165V as average real voltage in hwinfo64.
-VccST pulled down from 1.20V(Auto)
to 1.00V (in BIOS), reading 1.008V as average real voltage in hwinfo64.
Now the 8700k is cooler due to the reduced voltages, and it's stable through everything I can throw at it. Here's the memtest with the final timings I manually nailed in the BIOS:
So for your 3200Mhz RAM kit at stock XMP I'd say you could potentially even lower VccSA and VccIO more than I did (1.15V and 1.10V is my guess), and if you have those voltages at Auto they're probably too high and/or causing instability. VccST should always be fixed to 1.000V unless you are under liquid nitrogen cooling.
I hope that helps!