XPS Gen 2 Failure channel B dim 1

I am getting page fault errors ... bsod.  Dell diag tests return failures on Channel B Dim 1.

System board lists dims in a 1-3-2-4 order.  I was wondering if anyone knew which one was channel b dim 1.  Is this actually the b channel on dim number one (dual channel memory) or is it rather channel b on the system board and a different dim?  Thought I would ask here before switching up the dims to find the culprit.  :)  I have all four slots full of 1 gig mods.