About your settings in the PDF. I don't really recommend setting everything manually with the dual entries. Leave most auto and only use the MAIN MENU & AMD_OVERCLOCKING. Only VDDP & VDDG need to be set under AMD_CBS as safety. The DRAM training usually wants to mess with those otherwise on a failed boot.
I see you set both the P-state OC & AMD_OVERCLOCKING CPU OC. Leave the P-state & auto and either only use AMD_OVERCLOCKING or the main menu CPU_MULTI/voltage settings. It leaves the things less cluttered to know what went wrong/what was used?
Your problem with only getting infrequent success at boot is the same I get when running on the edge what the memory & motherboard/cpu can handle. I get the same behaviour running 4266/4X8Gb or 4600-4666/2X8GB. It's not just stable, board doesn't like running with the current parts @ that speed successfully. There are settings that can help and settings that can make it worse. You basically need to tune your settings to be more to your systems liking.
The settings I've seen to be primary are MEMORY timings,cad bus values & Data Bus Configuration. There are so many configurations possible you just need to start somewhere and test if it was better or worse.
Data Bus Configuration:
RZQ/7, RZQ/3, RZQ/1
RZQ/7, RZQ/2, RZQ/1
disabled, RZQ/3, RZQ/1
disabled, RZQ/3, RZQ/5
disabled, RZQ/3, RZQ/6
disabled, RZQ/2, RZQ/5
disabled, RZQ/2, RZQ/6
disabled, disabled, RZQ/5
disabled, disabled, RZQ/4
Test these out to see if any gives improvement. I had good luck with [disabled, RZQ/3, RZQ/6] for my E-die kits on the Aorus Xtreme.
Samsung B-die might like [disabled, disabled, RZQ/5] better as that is what I see other users report for those kits. (though I had bad experience with it refusing to boot too often)
CAD Bus Drive Strength:
24, 20, 24, 24 (is stock and works mostly ok)
24, 20, 20, 20
20, 20, 20, 20
30, 20, 20, 20
40, 20, 20, 20
24, 24, 24, 24
24, 20, 30, 30
This is pure testing, You just try different combos. This is mostly when I try to squeeze out errors that appear random and no timings seem to fix.
188.8.131.52 I usually needed for GDM:disabled 1T @ 3800/1900 but it was newer 100% error free. Random glitches would occur that didn't show in Error testing.
I'm currently trying different values to ~stablize~ 4266Mhz 4x8Gb as I still have Boot problems. Some combinations boot easier than others and others will cause errors, Still trying to figure out the best combo.
At higher frequency I've seen the higher values gives issues and likes these to be as low as possible.
CAD Bus Setup Timing:
AUTO, AUTO, AUTO is 99% safe for all settings. [0, 0, 0]
Safe values usually depends on your Memory kits I presume.
Most values don't work I've noted, ends up giving errors. But there are some combinations that just give you the extra edge to stabilize at higher speeds.
CkeSetup I can use 3-10 and it helps a little with the stuck/bad boots. Addr/CsOdt I've not found better than letting them be AUTO yet.
I usually found the higher the MEMORY frequency the lower you need to have this set to be stable/bootable. My E-die only likes 36.9Ohm @ 4000+ speeds. No other values work there.
Just don't run too low value, you will get odd behaviour like random reboots or USB glitches etc I saw. Having this "just right" is a thing and can be helpful rather than having it too high.
Too High and FCLK/Memory gives errors. Too low you get crashes in higher loads like Y-cruncher bench. 900-975 range seems ok but I've seen 975 can be too high if running higher OC and needed lower values there (4450OC with +1.450vCore) but 975mv was perfect for 4400 OC. This too probably has a "just right" value. Though it differs depending on other factors like CPU Clock, MEM, silicon quality etc.
I don't recommend going higher than [TURBO]. If you use [Turbo] you get the same voltage you set in BIOS with a DMM measured at the back of the cpu socket under load. Higher LLC will give you higher voltage than set in BIOS.
[Turbo] and higher have their issues with higher loads. They can shut off you computer suddenly if hit with a higher load as a spike. OVP OCP? I think OVP hitting and shutting down/rebooting if you run 1.400-1.450++ volts. The higher the LLC the lower the 'safe' voltage range goes without issues. Though I never adjusted the OVP/OCP settings and had them @ AUTO.
[High] doesn't cause this issue and what I'm using with AUTO OCP/OVP. I can then "safely run" 1.450+volts @4400-4450Mhz range if I want to check OC/stability. Though I don't recommend this to anyone, I'm probably soon frying it there anyway.