So I recently bought this Z77 motherboard used for 90$ and the seller let me also test it to see how it works, and everything ran fine with 16GB DDR3. Then when I got home, I installed it into my case, connected everything and went to turn it on. Then I waited like 5 seconds and I thought it was just because of the first boot with new hardware and then I see it shut down. It then automatically rebooted and I still thought it was normal since most motherboards do the same. Then it shut down again. At this point I turned off my power supply and first thing I did was check all the cables and try every RAM stick and slot. Every RAM stick worked which was expected and all slots also worked which I didn't expect. Then I tried putting 2 RAM sticks in dual channel and that also worked (which I am using right now). Then I tried putting the RAM right next to eachother which should never be done aaaaand it went into a boot loop. I also tried clearing CMOS just in case it kept some settings from the seller but that also didn't work. Right now I'm frustrated since I bought too much RAM as it seems and I can't handle the 8gb of RAM I have installed.
EDIT: If this helps, here are my specs:
i7-2600k @4.3GHz w/ be quiet Pure Rock Slim
GIGABYTE XTREME GAMING GTX 1060 6GB
8GB G.SKILL Ripjaws Series (2x4GB, DDR3-1600, have 2 more, but the motherboard doesn't want to work with all memory slots populated)
120GB Intel 535 Series SSD
1.5TB Seagate ST31500341AS
@AKBrian I tried it now and it works! Thank you very much for your answer! It could be that the motherboard was designed for the older 1.65V sticks so it doesn't really work nicely with 1.5V (I don't know, just a guess). Can a mod close this thread?