I'd like to know if my RAM configuration is ok.
I have:
- Mainboard: ASUS Prime x370 Pro -> 4 x DIMM, Max. 64GB, DDR4 (A1, A2, B1, B2)
- RAM-Kit 1: 2x16GB Corsair Vengeance LPX DDR4-3000 (CMK32GX4M2B3000C15)
- RAM-Kit 2: 2x8GB Corsair Vengeance LPX DDR4-3000 (CMK16GX4M2B3000C15)

My configuration:
A1: 16GB
A2: 8GB
B1: 16GB
A2: 8GB

When running CPU-Z it says:
Memory -> Size 48 GBytes / Channel # Dual / NB Frequency 1463.2 MHz /DRAM Frequency 1463.2 MHz

I'm not shure about this:
SPD -> Slot #1 is 16GB Dual, Slot #2 is 16GB Dual, Slot #3 is 8GB Single, Slot #4 is 8GB Single

Isn't A1 = Slot 1 / A2 = Slot 2 / B1 = Slot 3 / B2 = Slot 4?
And why are Slot 3+4 Single?

I'm also not sure about the Max Bandwith in CPU-Z: DDR4-2132 (1066MHz) - since I have DDR4-3000 (setting in BIOS is 2933MHz)

AIDA64 Cache and Memory Benchmark: 43766 MB/s (latency 89.2ns)

Thanks for any help!

 

Try swapping RAM sticks between Slots 2 & 3. Yes there are "should be/could be /would be", but that individual MB just might ignore it's purported specs. In the end, you'd like to see dual-channel on all 4, whatever pleases the MB firmware. Swapping the 16s & 8s could also work. Or a BIOS update. Getting a MB to work with RAM is often a struggle, and many of the settings are interactive. If that board is bitchy you may never get all of the parameters you want with the mixed sizes. So you live with the most important ones or upgrade the 8s to 16s.
Hey I downloaded the manual and pulled this :
"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."
Sounds like you live with dual/single mix or upgrade. Sorry.

 

@Left-Handed Reverb Thank you! I have now the latest BIOS, but still the same.
It's also mentioned: "4 x DIMM, Max. 64GB, DDR4 2666/2400/3200(O.C.)/2933(O.C.)/2133 MHz Un-buffered, ECC and non-ECC Memory"
So I overclocked it, but nothings changed.

I've read this before, but forgot it.. Hmmm, it just makes no sence to me.. it's mapping the lower-sized channel, but my channels got the same size, no? Unless I got the meaning of "channels" wrong! A1+A2 is one channel (16GB+8GB) and B1+B2 is also a channel (16GB+8GB). I'm probably wrong (I'm just reading myself into this).

 

you should properly read your motherboard manual for best ram placement and slot channel color and naming,
about speeds, those are most likely OC, so you need to choose 3000 in BIOS

 

should you not have equal sticks of ram? 4x8 4x16 4x32, thats what was told

 

The only solution is to sell one pair of these, either 8GB or 16GBs, and buy another pair of RAM sticks of the same size. It's written in the manual that you cannot mix sizes. Which is lame. I don't think I've seen that ever before.

 

hi guys, I have the Asus Prime X470 Pro, similar question: I have Corsair Vengeance LPX 2x8 3200 MHz, should I set velocity RAM in BIOS at 3200? or should I leave it as it is (around 2xxx)?

 

vs manual
'You may install varying memory sizes in Channel A and Channel B.'

At OP: maybe switching off Dual Channel mode in BIOS helps?

 

Thank you all very much!

just to make clear: I have/had no problems with my setting which is: A1 16GB / A2 8GB / B1 16GB / B2 8GB (and found out it's also the fastest)

I've read the manual, but it's not really precise about it (or I just don't get it ;-). I also read thru a thread in a more pc (pc for personal computer- if you know what I mean ;-) - related forum, where they say this board is a DIVA...

@SineWave: I didn't find this statemant in the manual -> 'It's written in the manual that you cannot mix sizes'
@No Avenger: That one I saw and it's what's running best for me -> 'You may install varying memory sizes in Channel A and Channel B.'

The other settings I've testet:
A1+A2 each 16GB
B1+B2 each 8GB
------------------------
A1+A2 each 8GB
B1+B2 each 16GB

With these settings it's the same with dual/single channels in 'cpuz': 16GB are dual and 8 GB are single.
AIDA64 benchmark is lower and for both it's around: 31'985 MB/s (vs around 43'800 MB/s with the setting in use)

So, manually setting RAM-speed in BIOS to 3000MHz does speed up benchmark in AIDA64, although it shows DRAM Status 2133MHz.

@JudoLudo accordingly what I wrote above: in your case I'd change the setting to 3200MHz (and let me please know what's written in DRAM Status for you!)

Conclusion (as some of you stated above): If I want all dual-channel I need 4x(the same size)GB RAM.
Does it make this much difference when all RAM are running in dual-channel? I don't know. For now I stay with this and it's cheaper ;-)
A1 16GB (dual)
A2 8GB (single)
B1 16GB (dual)
B2 8FGB (single)
Which gives me in AIDA64 benchmark: around 43'800 MB/s (latency 79.6ns)

The slots in 'cpuz' SPD tab are still strange to me (as I've mentioned in my first post)

Thanks again for all the replies!

 

The funny thing is, the manual states: '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.' But you got it right the other way around.

 

Why I said that it doesn't support differently sized RAM sticks is because In my view, when the "surplus" memory is mapped to work in single channel mode, that means it doesn't support differently sized RAM sticks. When memory works in single channel mode, the memory speed is halved and DDR4 is already working slower than DDR3, unless the frequency is set to 3200MHz and up.

Although, since we're talking 48GB of RAM, and this way 32GB of it working in dual channel mode, it doesn't actually sound that bad.

If we were talking 8 or 16GB of RAM, and half of it working at half speed, that would be quite bad.

 

Sell the 2x8gb ram and get identical sticks.