Did I install my ram wrong? 2x4gb, 2x2gb for 12 total....... screenshot inside!

[Sean Dempsey]

Did I do this wrong?

Each bank has a 4gig and a 2gig. I installed them into the machine with the 2x4gig on the left, and the 2x2gig on the right, and the "banks" are apparantly front and back, not side and side.


Would this make any sort of perceivable difference?

 

[Hellhammer]

It doesn't really matter. As long as it works and all RAM is utilized, you should be fine. I have only two slots and they are BANK0/DIMM0 and BANK1/DIMM0 so maybe the "right" way to install RAM is to have 2x4GB on the top and 2x2GB on the bottom or vice versa (it came with top slots populated, right?).

 

[Sean Dempsey]

It doesn't really matter. As long as it works and all RAM is utilized, you should be fine. I have only two slots and they are BANK0/DIMM0 and BANK1/DIMM0 so maybe the "right" way to install RAM is to have 2x4GB on the top and 2x2GB on the bottom or vice versa (it came with top slots populated, right?).

It did and I moved them. It came like this

2gig - 2gig
empty - empty

And now it's

2gig - 4gig
2gig - 4gig

 

[TMRaven]

I think if you want dual channel memory active, you'd need to have "bank 0" and "bank 1," which is what apple calls the channel a and channel b, to have matching density of ram.

In other words, you should have it where the totals for bank 0 and bank 1 are equal, in order to properly enable dual channeling.

This is true for intel boards, but I'm not sure if it's different or not as far as apple's proprietary boards are concerned.
http://www.intel.com/support/motherboards/desktop/sb/cs-011965.htm


Will you see a real world perceivable difference? Probably not.

 

[Hellhammer]

I think if you want dual channel memory active, you'd need to have "bank 0" and "bank 1," which is what apple calls the channel a and channel b, to have matching density of ram.

In other words, you should have it where the totals for bank 0 and bank 1 are equal, in order to properly enable dual channeling.

This is true for intel boards, but I'm not sure if it's different or not as far as apple's proprietary boards are concerned.
http://www.intel.com/support/motherboards/desktop/sb/cs-011965.htm


Will you see a real world perceivable difference? Probably not.

VirtualRain had an interesting insight about channelling:

The fact is no one knows for sure how the memory controller manages different mixed-matched DIMM's with any certainty. All anyone can do is guess or benchmark different combos to try and draw some conclusions.

https://forums.macrumors.com/posts/11239869/

I kinda agree with him, there is no way to tell is the config running in single or dual-channel unless you benchmark it. Also, according to Wikipedia, you don't have to use identical modules so maybe dual-channeling will work somehow with 4GB+2GB, I don't know. But as you said, the difference between single and dual-channel is pretty negligible