Dual Channel Memory Arrangement - Late 2013 iMac

[DOlsson]

Good afternoon all,

I was in Windows today on my iMac (via bootcamp) and I noticed that when I open up CPU-Z it's stating that my memory configuration is in Single mode. Should it not be in dual channel mode? There are currently two 8GB modules installed.

Perhaps I have modules in the wrong slots? (Apple installed them for me before I picked the computer up in store).

Does anyone have a definitive answer as to which slots (from top to bottom) the modules should be installed in?

Or maybe everything is fine and I'm misreading what CPU-Z/CPUID is saying. See attachments below.

Thanks again!

 

[Bear]

Hard to tell from what you posted. In OS X, in the System Information Utility, post a screen shot of the memory from there. I'm attaching a screenshot showing what you should post.

 

[DOlsson]

Thanks, will do when I'm home and not connecting remotely.

However, I found a thread that seems to have beaten this topic to death. I'll post the link below. But based on this long read, I think I know what I need to do (or what to check when I get home).

Here's the thread

 

[DOlsson]

Solved!

Ok, so I got home and popped open my memory bay and this is what I see.

The smart guys at the Apple store installed the ram like the little drawing below.


(Top of computer)

================== (8GB)
================== (8GB)
----------------------- (empty)
----------------------- (empty)

(Bottom of computer)


This resulted in my CPUZ application stating the memory was in "Single" mode.

I then rearranged the modules to look like this:


(Top of computer)

----------------------- (empty)
================== (8GB)
----------------------- (empty)
================== (8GB)

(Bottom of computer)


Now, CPUZ is reporting "Dual" for the channel, and I also notice that the Command Rate (CR) is reporting 1T vs 2T as before - so that's awesome!

Just thought I'd share my results.

Thanks!

 

[Johnf1285]

I noticed this too when I upgraded the memory in my 2013 27" (although slightly different).

"slot 1" ram (toward the top)
"slot 2" empty
"slot 3" ram
"slot 4" empty

I mimicked this when replacing the two stock 4gb sticks with two aftermarket 8gb sticks.

Reminds me of the PC building days.

 

[Bear]

I noticed this too when I upgraded the memory in my 2013 27" (although slightly different).

"slot 1" ram (toward the top)
"slot 2" empty
"slot 3" ram
"slot 4" empty

I mimicked this when replacing the two stock 4gb sticks with two aftermarket 8gb sticks.

Reminds me of the PC building days.

Why didn't you just add the memory instead of replacing it. That would've gotten you 24GB.

 

[Johnf1285]

Why didn't you just add the memory instead of replacing it. That would've gotten you 24GB.

I prefer to keep the same capacity, size, brand, etc., even across the board.

The new ram has faster timings with 9-9-9-28.

 

[Bear]

I prefer to keep the same capacity, size, brand, etc., even across the board.

The new ram has faster timings with 9-9-9-28.

Ahh the timing difference I can understand.