@Ket: I've so far only had limited experience with Vengeance modules but out of 64GB none wanted to run at rated specs in Dual-channel @ 1866 MHz with AMD A8-3850 "Llano", but we do have one "red" Vengeance-kit which will and also supplies OC-headroom to speak off...

Always thought this was a Llano problem but after reading your post it looks like I will go elsewhere for new modules which I am planning on purchasing. I am by no means an extreme memory overclocker but what you are describing just sounds awful.