they must have pulled it then as it most certainly was on the qvl although I think it stated v4.31 rather than v5.39 which is what the most recent versions are. good to know. I have to speak with corsair directly (might be slightly quicker rma so will see if there's an option to make sure they replace with v4.31, unlikely but you never know your luck) failing that i'll just return it and get something on the (current) qvl!
The reply i got from gigabyte tech support was
Hello,
CMK16GX4M2B3200C16(DS) is not listed in our QVL because it is not exactly the same as CMK64GX4M8B3200C16(SS).
AX370-Gaming is a 6-layer motherboard. Definitely, hardware layout (e.g PCB layer) plays a role in overclock but it’s not the only factor.
For DDR XMP performance on AM4 platform, it is more related to AMD AGESA code (APL code) support and CPU capability.
Also just tried the Hyper X its 2400 stock and wont boot to 3200 at all on xmp, tried F6 and F7, just boot loop over and over. and this is on the qvl!