Do you have dual CPUs installed as that DIMM slot is for the CPU2? 
Hi all, I have a T7910 in mint condition with the exclusion of the DIMM2_CPU2 socket which is damaged. The dimm population order effectively cripples this machine. If I want full speed memory I can at most only use four dimms. Is there any solution to this problem other than full mobo replacement? I find myself wishing there was a UEFI option to reverse the memory population order from "white" to "black". Thanks!  
T7910 - bad dimm socket