I've been doing a lot of searching and have not found any threads specific to this problem (either here or elsewhere on the interwebs) so I figured I'd actually come in here and post a thread.
I'm running a Gigabyte GA-AB350N-Gaming WIFI board with a 16 GB kit of G.Skill Flare X 3200 MHz CL14 kit on a Ryzen 7 3700X. I upgraded from a Ryzen 7 1700X with a 16 GB G.Skill Fortis 2400 MHz CL16 kit (on this same motherboard) so I'm not really surprised I've not run into the issue I am about to describe.
In the BIOS, when I set the 3200 MHz XMP profile for this memory kit, the BIOS posts and I can get into Windows just fine, but as soon as I login, instability hits and I either have tons of application crashes due to instability and then a BSOD (not the same BSOD, it changes depending on it's mood, I guess) or I just straight up get a BSOD before much can finish launching (this pretty consistently gives a MEMORY MANAGEMENT BSOD). If I leave the XMP profile on but drop the memory speed to 3000 MHz, I have no issues with stability whatsoever. Here are the troubleshooting steps I've gone through to try and get Windows stable with this memory kit:
Set VRAM voltage manually to 1.35v in the BIOS (just in case the BIOS was mis-handling the XMP voltage).
Set 3200 MHz speed without XMP on (the timings were horrendous, so that was pretty much a non-starter).
Use the Ryzen DRAM Calculator to manually set the timings both with XMP turned on and with XMP turned off.
Set the standard 3200 MHz XMP profile and ran MemTest86 to look for errors - no errors detected at the rated XMP speeds and timings.
Verified that the BIOS is setting FCLK and MCLK correctly automatically to 1600 MHz when the RAM is set for XMP profile at 3200 MHz.
Manually set FCLK and MCLK to 1600 MHz when the RAM is set for XMP profile at 3200 MHz.
Validated that when I drop my memory speed to 3000 MHz or 2933 MHz with XMP on that the FCLK and MCLK also drop to match automatically (these are both stable speeds in Windows).
At this point, I'm kind of at a loss of what I could possibly do to get this kit stable at it's rated XMP speed and timings. I haven't tried loosening to timings to something more along the lines of a CL16 rating because I'll probably get better results just running at XMP CL14 @ 3000 MHz than at 3200 MHz with looser timings. I suspect that the problem is the motherboard and the generally pretty terrible memory compatibility of this particular board. It's technically rated for 3200 MHz memory OC, but I think with the new CPU and this memory kit, it might just not be possible at this time.
Just to head this off at the pass, no, the kit I am using is not on the QVL for the motherboard. The kit's model number is close to some verified models, but a LOT of the kits on the QVL for this board are 4x configurations, which says to me they didn't do a ton of actual testing on this SKU since the board only has 2 DIMM slots. I think Gigabyte was doing "close enough" testing for this board, hence my problems today with a 3700X. At this point, I'm fairly willing to chock this up to a substandard motherboard and I'll just have to budget for a B450/X470 board that's Ryzen 3000 ready to get this kit working (don't really have the $$ for X570, or I would have done that already!). See specs below:
Windows 10 1903 64-bit (latest Chipset drivers from 7/31/19 are installed)
Ryzen 7 3700X
Gigabyte GA-AB350N-Gaming WIFI (rev.1) (Running the latest F42a BIOS, yay Destiny, finally)
16 GB 2x8 GB G.Skill Flare X 3200 MHz CL14 Kit (model #F4-3200C14D-16GFX)
Gigabyte GTX 1080 GV-N1080TTOC-8GD (modified with a 3rd party cooler was the blower was terrible)
Corsair SF600 600W SFX power supply
Samsung 850 EVO 512 GB SSD (boot drive)
Seagate 1TB HDD (2.5 in form factor, also terrible and slow)
Seagate 4 TB USB 3.0 External Drive
Thanks in advance!