According to the specs for the 8940 for 64 GB of total RAM you can have 2 x 32 GB or 4 x 16 GB but not the arrangement I am seeing in your post. That could be the source of the problem.
When I run the Dell diagnostics it locks up on the memory one. This is a screenshot from the Dell diagnostics of current config. It this correct or are the memory modules in the wrong slots? Thanks for any advice and wisdom, in advance. [IMAGE]
XPS 8940, won't run Dell memory diagnostics