I bought new RAM (crucial) for my 2009 MacBook Pro, upgrading 2x2GB to 2x4GB. When I install both 4GB sticks, I get the dreaded 3 beeps. I can install either of the 4GB sticks with a 2GB stick with success (proving that both sticks are indeed good), but not both. Any ideas on a next step?
MacBook Pro, iOS 12
PC-3 12800 is 1600mHz RAM. Is that what you have?
Yeah, that seems to be a common issue when attempting to use RAM of a higher speed than the required spec. When you described the issue, it was that clue that led me to suspect incorrect speed RAM.
Does it have specs as below?
| Memory Slots | 2 - 204-pin PC3-8500 (1066 MHz) DDR3 SO-DIMM |
|---|
2 204 pin PC3-12800 DDR3 1067 MHz
Yes - sorry
Ugh - and for some reason it will run with one 4GB 1600mHZ but not two?
If you have 1600mHz RAM, that would be the problem. The computer needs RAM as shown in my first post.
new RAM not working
