After some work with Dataram and Intel, the exact PN#s having problems in our lab are certified with CMTL (http://www.cmtlabs.com/x-cmtlpdfreports/018858.pdf)
As stated, I have had a number of these S1200KPR boards with the above Dataram report triple beep on boot. The testing performed in our lab uses 8 identical systems with the S1200KPR, DTM64395A DIMMs x2, Intel 520 SSD, and E3-1225v2. The procedure involves scripted hard reset of the units every two minutes - unless the unit boots and DOES NOT respond to ping. In this way, if the unit does not reboot as expected then it will be left in the failed state.
It seems to me that this test should NEVER result in a triple beep boot code failed state .... but it does on average of once every 50-100 reboots. Some systems exhibiting greater frequency than others.
We faced with very similar issue, but with Kingston KVR16E11/8 modules.With 2 such modules and any V2 CPU S1200KPR halts with 3 beeps 5-7 times from 10 power cycling.
Yes, this modules are not listed on Intel site, but here http://www.kingston.com/us/memory/search?DeviceType=8&Mfr=INT&Line=S1200KP&Model=73504 we can see it.
Looks like this is bios issue, which was not updated from 2012/Aug/1 for this board.