Xmp - maximum hero viii - does not work

[ostage]

Hi,
I'm having a problem with XMP and my maximum HERO VIII, I have in my standard configuration 2x4GB Corsair 3000MHZ in my pc if these rams are in and I enable the XMP the MHZ will go up to 3000MHZ in the bios and works without issue.

I've recently purchased another ram, same brand same model but 1x8GB and added to my configuration. When I plug the new ram inside if I leave in the bios AUTO on the ram profile works but with standard MHZ 2133MHZ, I try to activate XMP the post hung up with various error code usually 79, if I reset the pc a couple of time then starts but always 2133MHZ.

I've tried to use only the 1x8GB and try XMP but did not work.
I've tried with 1x4GB and 1x8GB and try XMP but did not work.

I've updated the bios to the last version (4/2018).

Any other suggestion?

Thank you for your help and time.

[Zka17]

Sell those Ram modules and get a proper kit (possibly from the QVL of that specific board)!

Mixing different kit/modules usually is not recommended... even from the same vendor, and same specs is a very high chance to not work. The reason is that the specs from the modules are only the part of a whole story - they are way more parameters to match (secondary and tertiary timings for example)*