I recently bought several RAM sticks and tried to upgrade total memory of my PC to 96GB. I have a Win 10 Pro, and according to Microsoft, there is no OS limit for such RAM upgrading.
I bought 4 Tridentz NEO G.Skill, each has 32 GBs.
Everything went well for the first two sticks, and I was able to upgrade the RAM up-to 64 GBs with no issue. However, when I added the other two, and got the total memory to 96 GBs, my PC won't boost. After I hitting the power button, the motherboard gives 3 long - 2 short beets repeatedly. I have checked a few sites, and could not find a clear clue on what cause the issue. The motherboard of my PC is IMP17-TP.
After taking out 1 RAM stick, the PC boosted as normal. I tried different combination of RAM sockets, and it seems the PC won't boost only when 4 RAM sticks are installed. Yet, after the system boost with only 3 RAM sticks, the system tells me 96 GBs installed while only 64 GBs usable.

Now I got totally lost.
Could somebody kindly tells me what caused this problem and how am I suppose to do to fix it? Thanks!