After digging some more, I have a new theory: I figure it could very well be an issue with the bios. It's likely it was never updated. At the time of purchase in 2015 it ran 2620 V3's (and I think was configured in the cheapest possible way). I'm trying to run 2660 V4's.The BIOS page explains older BIOS versions didn't yet offer compatibility with Broadwell (Xeon v4) cpu's. I think that could explain the malfunction as I feel the issue is probably pretty random, as an actual hardware issue would have been more obvious by now. Now here's the question:Can you update a Dell's BIOS by flashing it directly on the motherboard, without using Windows or the Bios settings? (As McTowerFace doesn't post) I know some manufacturer like MSI offer that option on their motherboards. Or do I just buy the cheapest Xeon v3 out there so I can make the update? (Considering my theory is correct).Tho I'd rather update the bios directly if possible, it would save me some trouble.    
Hello There, I recently bought a barebones T7910 which I'm building back up to workstation glory on the cheap. When trying to boot, it refuses to post. Power button blinks orange and is identified as (2,7) memory failure according to this diagnostics reference document. I currently have 4 sticks of 4Gb 2133Mhz RDIMM ECC memory, which is compatible with the system. (I do plan on getting more). I've tried every single stick in slot 1 but no change. I find it unlikely that all 4 sticks have a problem. I've also tried resetting the CMOS, which didn't work. At this point I have no idea what the issue could be, so here I am 
T7910 memory failure