GA-Z170-Gaming K3-EU overclocks memory by default?

[Kalpa]

TL;DR: I accidentally a wall of text. Anyone know if F3h (beta) BIOS (compared to F2 BIOS) will change factory default settings on BIOS so it will run memory at a conservative failsafe settings instead of immediately going for XMP settings?

First off, the machine:

Z170 K3-EU board 1.1 revision
Intel core i7-6700K CPU
MSI Armor Geforce 1060 6GB
(Kingston) HyperX Fury 4*8GB DDR4-2666 (XMP 2.0 profile included) memory kit
Thermalright Macho Rev. B (big-ass cooler tower)

BIOS version: F2

Greetings. I had a rather interesting time building this machine. I assembled everything listed, then proceeded to power on for first boot in anticipation of OS installation. Problem was, the machine didn't boot. Stuck on continous loop some 15 seconds in, then shutting down and repeating. (My theory is: stuck somewhere in the 'training' of DDR4 memory)

First I check the power cables, which all seem to be fine. Next up, memory (my usual suspect #1), remove all sticks and put one stick in, notice the machine posts just fine - allright, now to figure out whether the problem is with some specific stick, or some specific slot, crazy amount of memory stick swapping (my fingers still hurt, yes I'm an amateur without fancy tools) to find out that 1) all memory sticks work and 2) all slots work.

Well that's neat. I start up with one stick, go check out bios... and realize it's running the memory at 2666MHz, as if by *factory default* it is running XMP settings out of the box instead of some conservative and failsafe values.

Now, this seemed to be fine with one stick, and even with two sticks, but four sticks with default voltages etc. seems to be out of the reach for my motherboard (I haven't tried pushing it, reason follows). My problem is, the only way for me after a failed OC right now is to *physically remove* memory sticks from the machine so I can re-access UEFI setup to change settings (because factory defaults will give me a non-booting configuration if I have all 4 sticks in). You can imagine re-iterating with this is not a fun pastime.

So far I'm happy to run 4*8GB at 2133MHz, so far it has seemed quite stable. No super extensive memtest done, though. I'm not even that interested in pushing the memory any further, rather than I'm worried if (when) one day for one reason or another BIOS settings fail and they reset to factory default - and I'm forced to go rummaging inside the case, pulling off memory sticks (this stuff is giving me nightmares now)

My questions now: Have people had similar experiences with this motherboard and the F2 BIOS? Does anyone have experience with the F3h (beta) BIOS, and whether it might be of any help to my case (ie. it would factory default to conservative memory settings to guarantee boot)? The description states something about fixing some memory compatibility issues, but I haven't been able to dig any extra clarification on what it means - any experience, anyone?

[Kalpa]

Slight update, I've managed to get the system finally stable with 32GB of memory installed, memory running at 2133MHz. Had to raise IMC voltage from the default 0.96V to 1.1V for stability, though - an act which I find slightly strange, considering 2133MHz should be well within the specification of i7-6700K.

Looking at the SPD tables (as reported by CPU-Z) the memory sticks do have JEDEC settings down to 800(1600)MHz imprinted on them, however they also have JEDEC settings up to 1333(2666) - makes me wonder if the motherboard is not entirely to blame here, if the motherboard only looks up the 'fastest jedec' setting it can find on the stick at factory default setting? I have no clue how the actual process goes, though.

Any input on whether bios update to that F3h version would solve my BIOS defaulting to 2666MHz memory speeds after a factory settings reset would still be greatly appreciated. I'd rather not flash the bios in vain.

[Kalpa]

I took a leap of faith and flashed bios to F3h version today. I kept my fingers crossed on first reboot and while the new BIOS still defaults to (1333)2666MHz DRAM frequency, it actually manages to boot with that. In addition the machine appears to be stable with bios default configuration as well (going to run extensive memtest during the night, just to be sure, quick&dirty stability tests have found no problems so far)

I have no clue what default settings were changed for memory management in the update, as I can't spot a difference. I can only assume it messed around with the IMC timings section, or with a bunch of the other advanced settings I personally never touch (and barely understand). Basic DRAM timings seem to be exactly what they used to be with old bios defaults. It claims to run the IMC at the default 0.960V as well.