Yesterday I got time to test my "new" board, CPU and RAM. I got the X10SRH-CF, E5-2697Av4 and 4x32GB RDIMMS. The board booted but got stuck every time with code B7. I searched and found this error is related to RAM. I tried with only one DIMM but always got the same error. I tried updating the BIOS from the IPMI and also updated the IPMI fimware.
After this the board booted but now I got a different error. No matter what DIMM I installed, slot C1 always complained about an "uncorrectable error" and got disabled. As suggested in various threads and other forums I reseated the CPU, I cleaned and polished the contacts but the error persisted.
I almost gave up on a solution and would settle for 3 channel RAM and 96GB, as installed the fourth DIMM in another slot gave me the "improper memory configuration" error... But I found someone who took the board out of the case and it worked because a case standoff was shorting the memory pins. I took the board out and there's a fixed (non-removable) standoff that was shorting the pins on DIMM C1. Connected everything out of the case and it worked! So besides reseating CPU you can check that if you ever have that error.
I did a quick idle power consumption test and with 4 DIMMS and 1 SATA SSD it idles at around 100-110W in BIOS screen and around 50W when booted into linux. Enabling the onboard SAS controller added around 4W. When powered off it consumes 3W. Seems to be way more efficient than my current SB-EP server (X9SRL-F, E5-2650v2, 8x16GB DDR3L-1866), at least on idle, although don't know the exact figure without all disks.
Anyways, I should have better performance and save a bit on electricity, so I'm happy.