Hello thanks for choosing Dell and welcome to our community.

I suggest you use just one memory and see how it is. One CPU, one memory.

Respectfully,

Hi, so first I would´t use 2400 RAM with Gold CPU, it doen´t really match together.

So I would remove the CPU and take a look at the sockets if there´s no broked or damaged pins onboard. I already had this problem before with unrecognised RAM because of a damaged pin in the Processor Socket.

I would suggest to use intel GOLD in CPU1 and only test 1 memory, then 2 memory... all the way to 8pc of memory. 

If that works then you take all memory out and add CPU2 and slowly add the memory by 

A1 B1, A7

A2 B2, A8

A3 B3

A4 B4 A9

... etc

Steve