What was your Mac doing with the added RAM?
Keep in mind Samsung has a lifetime guarantee, I believe.
Personally, I like to go with high quality, Mac friendly RAM. No bargain stuff. The original Samsung RAM failed in my MacPro after 2 years so I'm not a fan of that brand. And Apacer is not what I would call Mac friendly at all.
I feel
Crucial RAM is the way to go. I have it in all three of My Macs, one of which has been running Crucial for 8 years now with no issues. It's a little higher priced, then some brands, but worth it and has a lifetime guarantee.
Crucial has a system tester that figures out exactly what RAM you need.
DALE