Might as well say I’m sorry if someone asked before.
Too many results where I didn’t find any info.
So.
My hardware
Asus ROG Strix Z270H Gaming
Intel i7-6700k @4.5
corsair 16gb (2x8gb) 3200mhz cl16 vengeance lpx black
And now I’ve got a new pair of sticks but they are
32GB (2x16GB) DDR4 3200MT/s CL16 FURY Beast Black RGB XMP
I know mixing ram and all that. The thing I’m wondering about is where to place them on the motherboard.
I’ve seen the way asus wants todo it but it’s don’t say anything about size.
16+16+8+8
16+8+16+8
8+16+8+16
8+8+16+16
I haven’t got the new parts yet and rather look for right answer.
I know on my hp elitedesk 800 g1 sff I had some problems with different sizes. But that time it was same everything but the size.
You may install varying memory sizes in Channel A, and Channel B. The system
maps the total size of the lower-sized channel for the dual-channel configuration. Any
excess memory from the higher-sized channel is then mapped for single-channel
operation.
I think that 1 and 2 are Channel A, 3 and 4 are Channel B.
2 and 4 are the recommended slots IF you are using only 2 DIMMs, but they are still seperate channels.
@Zszywany I think I had a brain fart and mixed up Channels with Channel Sets. Sorry.
But looking at that mobo manual has confused me some more. Normally A2&B2 are one colour, and A1&B1 are a different colour, to guide the user into installing pairs of DIMMs into those slots. That mobo has A2 one colour and all the rest the other colour. Which suggests… it doesn’t matter any more?
Is that because it’s a T-topology layout as discussed by Buildzoid in this video?
With support for DDR4 memory, ROG Strix Z270H Gaming lets you drive memory frequencies to 3866MHz and beyond when overclocked! ASUS-exclusive T-Topology circuit design provides superb memory-overclocking capability to unleash the full power of DDR4 by minimizing coupling noise and signal reflection. With innovative equidistant memory channels, T-Topology delivers balanced control and powerful overclocking compatibility.
So all slots have equal trace length and (assuming no controller or BIOS muckup) the same performance.
But I was unsure what was right.
Not same motherboard.
The HP when I had 2 corseair and 2 crucial all was 4gb sticks.
That time I used pair 1-3 and 2-4 but when I changed to 2x8 sticks i had to use 4-3 and 2-1 for it to work.
And I did start with I’m sorry!
And for me that’s a bit stupid and don’t always know how too search in the best way in English.
You may install varying memory sizes in Channel A, and Channel B. The system
maps the total size of the lower-sized channel for the dual-channel configuration. Any
excess memory from the higher-sized channel is then mapped for single-channel
operation.
In a 16+16+8+8 configuration, Channel A has 32GB and Channel B has 16GB. The lower-sized channel is B, so all 16GB of B and the same amount (16GB) of A is accessed in dual-channel mode, leaving the excess 16GB of A to be accessed in single-channel mode.
In a 8+16+8+16 configuration, Channel A and Channel B both have 24GB. Thus there is no excess, and ALL of the memory is accessed in dual-channel mode.
I would contend that the second configuration will outperform the first.
Specifically: If the memory controller is smart, it will preferentially use dual-channel memory before resorting to single-channel memory. Thus the two configurations above will perform identically when actively using 0-32GB of memory, but the second configuration will perform better when actively using >32GB of memory. If the memory controller is dumb, it will ignore channel mode completely and semi-randomly access memory. In that case the second configuration will perform better regardless of how much memory is actively being used.
PS: Because the motherboard uses a T-topology layout for traces:
Yes, that is what it says, but I think that it is assuming all of the memory is exactly the same. In your case, the memory is very similar, but not exactly the same. The capacities are different, so there may (and indeed seems to) be a preferred way.
No need to apologise. Questions are good! The whole T-topology thing managed to slip right under my radar, so you asking the question — along with the other responses — forced me to look into it and update my knowledge base. I’m glad you asked!
As a default you want both channels equal with the bigger dual-rank kit closest to the CPU, but as stated the latter doesn’t matter on this particular motherboard because the traces are all equal length for maximum stability.
As an anecdote, HP Prodesk/Elitedesk have the DIMM slots in reverse order (4-3-2-1), for reasons I have to assume are to do with network booting and such using the vPro’s. From experience I know they won’t boot without DIMM1 populated.
