Adding an extra stick of RAM gives me random crashes

Hi folks, been meaning to create a thread on this issue of mine for awhile now but had no opportunity except now. I have attached the diagnostics per instructions. The scenario before: I was using a 2TB HDD and was using x2 4GB Crucial Ram and x1 8GB TeamDark Ram (this one: Team Dark 8GB 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model TDD38G1600HC901 - Newegg.com) and was running fine, no crashes or anything. I switched over to SSD a year or so ago, same RAM placements, and it's been randomly crashing on me.

My motherboard is Gigabyte GA‑Z68AP‑D3. I have also performed Memtest86 on all 3 RAMs, successfully all three. If I had missed anything, or if there's any recommendations, I'd highly appreciate it as I do not know what the issue is that are causing these crashes. I have since removed the x1 8GB stick (last crash was yesterday [11.10.2015]).

Layback Bear said:

Just a note:
Any time one mismatches ram problems can occur.
Ram should be matched. All the same manufacture, part number, volts, speed ect.
You can buy matched ram in one package.
All matched ram are tested to play well with each other.

I'll keep that in mind, is this always the case though?

axe0, maybe it is because I took out that RAM? I'm not sure, I guess I'll chuck it as a loss that that RAM does not match. Thanks all.