ASUS PRIME z270-A, dual M.2 - are both slots at full speed?

[Bongolongo]

Hello,

I have a question regarding this motherboard: https://www.asus.com/us/Motherboards/PRIME-Z270-A/specifications/

It has two M.2 slots, but their descriptions are different (quoted below). I'm unsure whether both slots will be able to run a Samsung EVO 960 SSD at its full capacity?

(The SSD: http://www.samsung.com/us/computing/memory-storage/solid-state-drives/ssd-960-evo-m-2-500gb-mz-v6e500bw/)

About the motherboard slots, from ASUS:

- 1 x M.2 Socket 3, , with M Key, type 2242/2260/2280/22110 storage devices support (SATA mode & X4 PCIE mode)*1

- 1 x M.2 Socket 3, , with M Key, type 2242/2260/2280 storage devices support (PCIE mode only)*2

*1. The M.2_1 socket shares SATA_1 port when use M.2 SATA mode device. Adjust BIOS settings to use a SATA device.
*2. The M.2_2 socket shares SATA_56 ports when use M.2 PCIE mode device in X4 mode. Adjust BIOS settings to use M.2 PCIE devices in X4 mode.

They're different but both can run as PCIe - that's the fastest kind, or am I mistaking?

Thanks!

 

[kanewolf]

The one that runs in X4 mode will be the fastest. It has the most PCIe lanes available. I think the other slot has 1/2 the number of PCIe lanes (2 vs 4).

 

[Bongolongo]

The one that runs in X4 mode will be the fastest. It has the most PCIe lanes available. I think the other slot has 1/2 the number of PCIe lanes (2 vs 4).

Thank you for your reply.

Do you know how much x4 and x2 represents in speed?
I'm wondering if the slower one will still be fast enough for 3,200MB/s Seq. Read and 1,800MB/s Seq. Write?

 

[kanewolf]

To get the 3200MB/s you need the X4 interface. Either one of those is at least 3X SATA rates, so either one should be better than what you have today.

 

[Bongolongo]

To get the 3200MB/s you need the X4 interface. Either one of those is at least 3X SATA rates, so either one should be better than what you have today.

Ok, thank you for your time.

 

[Bongolongo]

To get the 3200MB/s you need the X4 interface. Either one of those is at least 3X SATA rates, so either one should be better than what you have today.

Hi Kanewolf, I had a second look around for information, and found this on wikipedia

M.2 sockets keyed for SATA or two PCI Express lanes (PCIe ×2) are referred to as "socket 2 configuration" or "socket 2", while the sockets keyed for four PCI Express lanes (PCIe ×4) are referred to as "socket 3 configuration" or "socket 3"

Would that mean that both slots (listed as socket 3, although they have the different desciptions) actually are able to run at x4, thus running the Samsung EVO SSD at full speed?

 

[kanewolf]

I don't know, the manual isn't very clear. If you have the motherboard, the best answer is to benchmark it. If you are asking these questions for RAID, it is a really BAD idea for most people.

 

[Bongolongo]

I don't know, the manual isn't very clear. If you have the motherboard, the best answer is to benchmark it. If you are asking these questions for RAID, it is a really BAD idea for most people.

Not RAID, but I plan to first get just the one SSD and later the second as a dedicated Photoshop Scratch Disc while operating system and other software occupies the primary.

 

[Bongolongo]

Asked ASUS and they came back with this, if it should help someone else.

"There is no real difference between the slots in relation to speed, however it depends a bit on the bios settings you use but generally speaking you will get the same speeds out of both connectors."