So i got 2x4 GB of corsair vengeance pro (1866) at the beginning of this year and i wanted to add another 2x4 of the same model. Even tho they have the same frequencies (1866) they don't work if i stack them but work individually(only the 1st stack alone in my computer or only the seccond stack but no combinations). The only thing that i saw different on them are the ver8.22 on the one i bought 1st and ver 4.19 on the ones i bought last but the guy from the shop told me that's not a problem they should work. they are 9-10-9-24 but if i let my bios auto tune them they go to 9-10-9-27 anyway none of the settings work. I'm trying to combine them on a 990fxa-ud3 motherboard. Do you think that the ver difference is the problem ? and if not what suggestions do u have. Thanks !!!