No, if you don't want to believe me I can't help you, I can't explain it anymore than I already have. I will explain your example though, if a Sumo wrestler is sitting on your cracked rib, but it didn't break right when he sat down, it will eventually and usually sooner rather than later.
Sorry for the BIOS confusion, I looked back to see which board you had and missed your UD3R and though your post was nhphuong
's that was UD5
Great you attached some images, but where is the several images of the CPU socket pins I've been asking for? Please take from a few angles, thanks!
No memory stick should be used in slots DDR3_2, unless DDR3_1, DDR3_3 and DDR3_4 are filled already.
Memory should only be used in DDR3_5 or DDR3_6 in certain scenarios (last two slots by 24 pin), unless either 1, 3 are filled too (other two white) then you can put one in DDR3_5.
Or if you are using 4 modules in triple channel and than would be 1, 2, 3, 5 (As labeled)
Or when all slots are filled already and then last blue slot would be DDR3_6 filled with last module.
Any of the 8GB sticks are going to give you problems unless you set things manually, since they are not designed for X58 chipset (ie 10 year old chipset).
Mainly the problem settings would be tRFC and tFAW (both would be set too low by auto or XMP for use with X58 chipset, especially tRFC), tRRD may also need loosened auto is apply 6 or 7 by default.
This is due to the default SPD timings would be very different for the modern chipsets those are designed for. Please show me an image of CPU-z SPD tab for one of the 8GB sticks, or AIDA64 SPD with one of them selected (And spread out the value area so I can read all settings)
If you do not have AIDA64, HWinfo64 is free and will be just as good, scroll down so I can see all the profiles and settings on the SPD section for one of the modules.
And for the 8GB sticks you would also need to adjust voltages as mentioned before, auto will give either too high or too low for QPI/Vtt (you can see current applied QPI/Vtt voltage with Easytune).
I cannot remember if HWINfo will show you this voltage, but I don't think so, BIOS will not show actual (grayed value you see is not applied voltage)
If you do not want to do this, voltage changes and sending images etc, I can't continue to try and help you with these modules.
If this is the case, please test only the 3x2GB sticks in the white slots since those were designed for this board I can help you on those without having to see all that I asked above.
Also, since you are using unsupported CPU in BIOS that has old microcodes in it, I suggest you upgrade to a BIOS with updated CPU microcodes.
Here, I posted updated one with 2015 microcodes in it long ago for someone else here but I can't find the page, so here is new upload (Flash with Qflash or FlashSPI, do not flash with @BIOS
In the end, it very well could also be a faulty or weaker memory controller in your Xeon vs your old 930, but I bet it can be addressed to stability with proper settings.
They do have different memory controllers, and different uncore properties too, all this affects how memory runs and memory stability/instability.