3 Sticks of RAM iMac 27" Late 2013

[Gazmo]

Hi Guys,

I'm after some advice please with RAM I am about to install into my late 2013 iMac.

So it came preloaded with 2x 4GB and I've just bought 1 x 8GB from Crucial. Now my question is - am I able to install the 8GB in 1 slot and then keep the 2x 4GB in the same slots? Is it safe to do so?

I plan to get another 8GB next month to have 2x 8GB and 2x 4GB = 24GB - would this setup still work in dual channel?

Thanks.

 

[drambuie]

If you leave the Apple 4GB DIMMs in their original slots and place the 8GB in the empty slot between them, you will have the optimal setup for 3 DIMMs. The setup should be:

Slot 1 - 4GB
Slot 2 - 8GB
Slot 3 - 4GB
Slot 4 - Empty

The two 4GB DIMMs will work in dual channel mod, and the 8GB will be in single channel mode, with a slight 8 to 10% memory performance hit, only when accessing the upper 8GB. When you fill slot 4 with another 8GB the full 24GB will be in dual channel mode.

Just make sure the 8GB modules are the exact match for the originals in frequency and CL latency.

 

[desantii]

dont you need it in pairs?

 

[redheeler]

dont you need it in pairs?

You don't need it in pairs but there is a slight performance dip from not having matched pairs. Compare that to a G5 where not having matched pairs is as good as having no memory at all.

 

[lchlch]

You don't need it in pairs but there is a slight performance dip from not having matched pairs. Compare that to a G5 where not having matched pairs is as good as having no memory at all.

If you put in 3 sticks all the memory sticks will run on single channel mode. Which would result in a 3%~7% reduction in performance.

 

[Gazmo]

Thanks guys.

 

[NDS]

If you leave the Apple 4GB DIMMs in their original slots and place the 8GB in the empty slot between them, you will have the optimal setup for 3 DIMMs. The setup should be:

Slot 1 - 4GB
Slot 2 - 8GB
Slot 3 - 4GB
Slot 4 - Empty

The two 4GB DIMMs will work in dual channel mod, and the 8GB will be in single channel mode, with a slight 8 to 10% memory performance hit, only when accessing the upper 8GB. When you fill slot 4 with another 8GB the full 24GB will be in dual channel mode.

Just make sure the 8GB modules are the exact match for the originals in frequency and CL latency.

Is the same true for a;
Slot 1 - 4GB
Slot 2 - 16GB
Slot 3 - 4GB
Slot 4 - Empty

 

[TouchMint.com]

I was wondering this same question. I ordered 2 8gb sticks of ram but they sent me a 16gb or ram so now I’m stuck with 4 4 and 16. What is the best way to possition these? Am I better off removing the 4 and 4 and just using 1 16? Or should I go 16 4 4 empty?