I bought a 5K iMac 4 months ago, with the stock 8gb of ram. I bought an extra 2x4GB off Amazon (Crucial Ram). But then, it looks like I cannot use all 4 ram slots at the same time. The iMac won't even start, only show a black screen. The Crucial ram sticks are 100% working, since I tried removing the original ram sticks, using only the new ones, and the mac boots and runs fine Right now, I am running the iMac with 3 of the 4 sticks, so at the moment I have 12gb of ram. I tried using the top 3 slots, it works. Bottom 3, it works. 2 slots works too. But as soon as I insert a 4th ram stick, it stops working I have resetted the SMC and NVRAM. Still no luck Also updated Mojave to 10.14.2 (latest version)
Any ideas? I would like to see if there's anything I can try before setting an appointment with Apple for this, since it's my main working machine, and I need to work on some projects right now.
Thanks a lot!
Here's the Ram kit I have bought:
Crucial 8GB Kit (4GBx2) DDR4 2400 MT/S (PC4-19200) SR x8 SODIMM 260-Pin Memory
I've read multiple comments on Amazon about this kit working fine with 5k iMacs...so I'm not sure what's going on here. Thanks