PC3-14900 DDR3 in iMac 2010?

[MarvinHC]

Hi,

I bought from someone who upgraded his brandnew iMac (late 2015 5k) two RAM sticks of 4GB to upgrade my iMac 27" from 2010. The memory got recognized but then within short time freezes. I realize the memory is faster than the original one (1867 MHZ) but I expected it to simply run on the slower speed but otherwise would work. Anybody else having an experience with fast RAM in an older iMac? Anything I am missing?

 

[dictoresno]

I thought RAM had to be perfectly matched to what the original computer specified for.

 

[MarvinHC]

I thought RAM had to be perfectly matched to what the original computer specified for.

Normally faster is not an issue - the internal bus will slow it down - hence my surprise.

 

[dictoresno]

Normally faster is not an issue - the internal bus will slow it down - hence my surprise.

Gotcha

 

[errin]

Some macs have an issue with RAM that's not the same as factory specs. My 2008 is working fine with higher bus model but 2010 model need the exact same bus or it won't boot.

 

[MarvinHC]

Well it does boot and also recognized it the modules when looking into 'about my Mac'... but shortly afterwards crashed and same thing after I rebooted... I also put two of the original 2GB sticks in (in addition), will try tonight only with the two new 4GBs (which defeats the purpose however, I wanted to go from 8GB (4 x 2GB) to 12 GB (2 x 2GB + 2 x 4GB))

 

[MarvinHC]

For future reference:
I tried all combinations (1 x (new) 4 GB in (each one of the two separately tried out), both 4 GBs in, etc etc. and none of them worked. As soon as I put the original 2GB x 4 back in the iMac was stable again.

So in short: no, the faster 1867 MHZ RAMs do NOT work in the iMac 2010. Next I will try them in my MacMini 2012.

 

[redheeler]

Interesting. 1600 MHz RAM is stable in my mid 2010 27" iMac but reports as downclocked to 1333 MHz.

Unlike your iMac, the 2012 Mac Mini should accept 1867 MHz fine.

 

[MarvinHC]

Interesting. 1600 MHz RAM is stable in my mid 2010 27" iMac but reports as downclocked to 1333 MHz.

Unlike your iMac, the 2012 Mac Mini should accept 1867 MHz fine.

I hope so. I think the mini has either 1333 or 1600 2 x 4GB inside at the moment, so this way I could transfer these to the iMac and get the desired 12GB of RAM there.

 

[MarvinHC]

Final update: The 1867MHC RAM works fine in a 2012 Mac Mini (recognized as 1600 MHZ), so the slower RAM I had in there has now been transferred to my iMac so happy all around