I've accumulated several boot warnings and/or errors during boot. I'm
not sure which ones are innocuous, and which ones are a problem:

These, especially the bug one seem concerning from the associated
comment in the kernel source:
[Firmware Warn]: MTRR: CPU 0: SYSCFG[MtrrFixDramModEn] not cleared by
BIOS, clearing this bit
[Firmware Bug]: ACPI: BIOS _OSI(Linux) query ignored

I don't see any specific problems from this one, at least I don't
think I do. The only PCI related issue I'm currently aware of is my
docking station not working properly if I unplug it or plug it in
while the laptop is suspended. (eg, resume state is different than
suspend state)
PCI: Ignoring host bridge windows from ACPI; if necessary, use
"pci=use_crs" and report a bug

Odd...maybe just a chipset quirk?
HPET not enabled in BIOS. You might try hpet=force boot option

I'm not sure if these are enough to warn the user about. I imagine
some discussion went into the notice though.
pci 0000:01:00.0: disabling ASPM on pre-1.1 PCIe device.  You can
enable it with 'pcie_aspm=force'

A quick search of these messages makes them seem pretty common. I'm
not sure what an HEST or ERST table is, but is the warning useful in
some way?
HEST: Table is not found!
ERST: Table is not found!

My understanding is that memory region issues are common, but don't
usually cause a problem and when they do, its useful to have the
message in the logs, so eh.
pnp 00:09: disabling [mem 0x00000000-0x00000fff] because it overlaps
0000:00:12.0 BAR 6 [mem 0x00000000-0x0007ffff pref]
pnp 00:09: disabling [mem 0x00000000-0x00000fff disabled] because it
overlaps 0000:01:00.0 BAR 6 [mem 0x00000000-0x0001ffff pref]
system 00:01: [mem 0xfec00000-0xfec00fff] could not be reserved
system 00:09: [mem 0x000e0000-0x000fffff] could not be reserved
system 00:09: [mem 0xfff00000-0xffffffff] could not be reserved

Seems to be related to video switching ACPI event related to radeons
(drivers/gpu/drm/radeon/radeon_acpi.c):
failed to evaluate ATIF got AE_BAD_PARAMETER

EDAC amd64 spits out a whole bunch of information ending with an
EINVAL. Seems a bit overkill when its just detecting that the hardware
isn't there. Perhaps this is just the fault of the distro kernel
configuration.
amd64_edac: probe of 0000:00:18.2 failed with error -22