Did some extra homework on the PCIe lane thing and thought I'd post it here instead of my other thread (since I'm talking about it here). So within MSI they have these particular three boards: Z270 Gaming Pro Carbon, Z270 Mortar, and the X299-A Pro. Their PCIe layout is quite interesting:
That makes:
- The ATX board quite the usual
- The Z270 mATX board basically an oversized ITX board with the extra PCH lanes
- Something almost all AMD mATX boards suffers from
- The X299 mATX board a more flexible and logical alternative, but also potentially more expensive.
EDIT: even more digging:
Now outside of MSI, the proposition of the X299M KBLX board diminishes, because:
- if one just want an i7 and mATX, Asrock's Z270M Extreme4 and Gigabyte's Z270MX Gaming 5 got both covered. Those boards already does x8 x8 x4-ish, so why more $$ on it unless maybe wanting that 5ghz?
- if one wants x8 x8 x4-ish and an X299 and an mATX, the EVGA X299 Micro board actually makes better sense, especially the off-chance of switching to a SKL-X CPU if that apple ever falls. (bonus points for CPU heatsink clearance)
- EDIT: yeah a hole in this argument: KBLX CPUs on EVGA's X299 will be set in x8 x8 and there's no switch for it to go x16 x0, so there's that argument for MSI's KBLX board
- If one wants two m.2 slots, that Asrock board and the Asus Strix Z270G got that covered (although the Asus board does x1 from the PCH on the last slot)
That being said, I think the X299-A is mostly covered by other Z270 boards already. Except becoming feverishly fast, but that's about it.
Oh yes, I looked up AMD's mATX offerings as well. Not one of any is willing to split that x16 from the CPU.