Looks like it's a V4 CPU incompatibility.  I'll try to find an older V2 or V3 proc and give that a shot.  If it works i'll update the BIOS and put the big boy CPUs back in.  edit: V2 isn't compatible but i found a V3, and it's working now.  Hooray!
Hi all, I have an R730 system with original (1.0.4) bios, and I can't get it to boot past this point with even a minimum configuration of DDR4 DIMMs.  Is it possibly a problem with too new of a CPU?  Were there components that weren't compatible with the original bios that were added in later revisions?  Let me know, i'm kind of stuck at the moment.  Thanks!  
R730 "Configuring Memory........Done" hang