Late 2015 iMac: Same spec RAM - still not playing nicely together

[maves_1]

Hello,

I recently bought 2x8gb @1867ghz sticks of RAM to add to the 16gb (also 2x8gb @1867ghz) that is in my late 2015 iMac.

Despite tracking down RAM that is the same brand, clock speed, and latency; when installed together, the system shows the speed as 1333ghz.

https://imgur.com/dhgDVM1

I've attached a picture of the old and new RAM. Is there something I'm missing? Is there any reason these sticks should not be completely compatible?

 

[jaslion]

Hello,

I recently bought 2x8gb @1867ghz sticks of RAM to add to the 16gb (also 2x8gb @1867ghz) that is in my late 2015 iMac.

Despite tracking down RAM that is the same brand, clock speed, and latency; when installed together, the system shows the speed as 1333ghz.

https://imgur.com/dhgDVM1

I've attached a picture of the old and new RAM. Is there something I'm missing? Is there any reason these sticks should not be completely compatible?

The only time you can be 100% sure your ram will work togheter is, is when you buy a complete kit. These things can happen when you mix different kits no matter how similar.