Ok I have to admit I'm lost. XMP profile is now OK. Most of the time, when I changed something in the Bios, it would reset it.
I have absolutely no idea why it's doing that. The only thing I changed though (while trying different things) was disabling CSM.
And guess what?
My PC has been working and booting normally (and quickly) since then.
I haven't decided to return my MB yet as a result. Memtest (done in Dram calculator) and OCCT reported no problem, it seems to be working normally.
I could leave it like that and see where it goes! ....
Or I could try to tighten ram timings a bit )))
Oh, and I also flashed the bios again, I thought maybe something didn't go the way it should at first.
Even if it continues to work, I know I'll be flashing the bios again as soon as a new one comes out ^^
I have had a similar issue with my MSI Meg Ace. CMOS keeps resetting after being shutdown for about 30 minutes. Battery if fine (tried another to be sure), no issues with Windows, just that my CMOS keeps clearing. From what I can gather this may be a Ryzen 3000/BIOS compatibility problem. Maybe it is the board though.