Placed the two modules that are passing the test in another computer, error
So you put the ram you thought was good in another motherboard and it failed memtest? I’d interpret that to mean one of 3 things
A) the problem is in one of those modules you switched
B) separate problems occurred on both motherboards either due to unrelated issues or the memory being seated incorrectly (this is really unlucky)
C) there’s a problem with the modules you switched and an unrelated problem either in the other modules or in your primary motherboard (you poor bastard)
Did you take note of where in memory memtest was finding errors? If it wasn’t in the same general area between runs then its more likely to be a motherboard issue.