Question Mixing RAM from the same purchase fails Memtest

[iampowerslave]

Ages ago I bought two Intel DH67BL boards, two i5-2500 and six 4GB Kingston PC1333 sticks of RAM (all six in the same purchase and same model)
One machine was configured with two sticks of RAM (8GB)
The other machine was configured with four sticks of RAM (16GB)
Years went by and I bought 4x8GB for one machine and decided to add 2x4GB to the other one using the used modules from the other machine.
No luck. If I mix the modules (same brand, date, etc) used in one machine with the other two used in another machine, Memtest fails. If I use all four modules that composed the 16GB into the other machine, they work fine. Memtest Passes

How on earth, I can't mix the modules used in one machine with the ones used in the other?

 

[Lutfij]

Intel DH67BL boards
Those boards were so bad, that you needed to follow through the memory QVL strictly, in fact they were also a good benchmark to the quality of the rams used on the board, I used Mushkin Redlines on a client's board and it was snappy btu when I dropped in locally sourced, Transcend sticks of ram with seemingly the same specs(not latencies), the PC refused to boot or if it did POST>OS GUI, there were errors galore.

One more thing, Intel boards never liked mixing and matching sticks of ram. Other motherboard makers were slightly laxed about it but you'd still see instability.

You will need to source something that is a matched set and have a high pedigree with their IC binning process. I wouldn't drop anything on them unless they are very cheap when sourced off of Ebay.