Asrock Z170M Pro4s - DDR4 Memory 2x or mixed?

[tclilly]

Hello I have a Asrock Z170M Pro4s motherboard. It takes DDR4 memory.

Can I put in the motherboard a 8gb (Crucial) and a 4gb (Crucial or Corsair) stick in the same channel? (2 sticks total)
OR
Can I put 2x 8gb (Corsair) in one channel and then put a single stick 8gb Crucial in the other channel by itself. (3 sticks total)

 

[BadActor]

Neither of your options will run in dual channel. They have to be matching sticks, the reason they sell kits.

 

[tclilly]

thanks so much so i should just go with my 2x 8gb Corsair for now? and return the 8GB crucial, or i could just buy a second 8gb crucial for a total of 32gb

 

[Tradesman1]

If you put the sticks in different channels, yes some part of it will run in DUAL - say 8 in A and 4 in B, then 4 from each channel are in dual (8GB total) the odd 4GB from the 8GB stick runs in single channel mode - this is part of Intel's Flex technology which has been arounfd for years, more on it in my article DDR3 FAQs, Item &

http://www.tomshardware.com/answers/id-2741495/ddr3-faqs-fiction.html

Big thing will be if the sticks will even play together, there are no guarantees, even with the same exact model (covered in Fiction, items 2 and 6

 

[geofelt]

If you want 32gb, buy a 32gb kit and return all you have if you can.
You can buy a 2 x 16gb kit for about $220
Or, a 4 x 8gb kit for $150

Ram is sold in kits for a reason.
A motherboard must manage all the ram using the same specs of voltage, cas and speed.
Ram from the same vendor and part number can be made up of differing manufacturing components over time.
Some motherboards can be very sensitive to this.
That is why ram vendors will NOT support ram that is not bought in one kit.
It is safer to get what you need in one kit.
But, it is a bit more expensive because of the added matching of all the sticks to insure compatibility.