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usernameistoosh · ‎02-04-2019

Just bought the Z390-I, which uses the mITX form factor. It has 2 x M.2 slots and 4 SATA6 ports. I'm waiting on my NVMe drives to arrive, so I can't test things out myself at the moment. if anyone can clarify how my proposed setup would work. There's something I'm not sure about.

So, the idea is to use two M.2 drives in NVMe mode (one drive will be dedicated to Windows, the other drive will be dedicated to Linux - I specifically don't want to partition a single drive for both OSs. Both drives are Samsung 970 EVO). Now, I have two other SATA6 drives that I want to use for general storage purposes. Those two drives are Samsung 860 Pro.

In the manual it states "When the M.2_1 socket is operating in SATA mode, SATA port 2 will be disabled." I get that. However, my M.2 drives will not be in SATA mode, but NVMe (i.e., PCI-e) mode.

1) Will any SATA6 ports get disabled if both my M.2 drives are in NVMe mode? I'm seeing posts on this forum and for mobos of other manufacturers that, in-fact, NVMe mode will still disable SATA6.

2) Will I be able to run both M.2 drives at full speed? From the overview page (https://www.asus.com/Motherboards/ROG-STRIX-Z390-I-GAMING/overview/) I see it listing "1 x 2242-2280 (at front) supports SATA & PCIe 3.0 x4 modes ; 1 x 2242-2280 (at rear) supports SATA & PCIe 3.0 x4 modes" and "1 x PCIe 3.0 x16" (for my discrete GPU). So I'm guessing from this that I will be able to maintain full speeds for both drives, but not sure because I can't seem to find any info on the total number of lanes. In other words, the two M.2 ports may be capable of independently running at x4, but as soon as you put two drives together the x4 goes to x2+x2. That's what I'm not sure about.

Ch3vr0n · ‎02-05-2019

You said it yourself when the M.2 sockets are operating in SATA MODE (aka SATA BASED M.2 drives), sata port 2 will be disabled. Since you're using NVME drives that issue is moot. I was wondering the same thing back on my M8F because on 1 page it said even with nvme drives a sata port with be disabled and on another it said no port would be disabled. Hooked up an M.2 nvme drives, all SATA ports were operational.

I'm now running an M11F, both M.2 sockets are occupied with NVME drives and all 6 sata ports are still working.

Speedwise you'll be more than fine. Not to brag but my M11F has triple the PCI-E x16 slots double nvme slots and everything (samsung 960 pro 512GB, 970 EVO 2TB and 4 HDDs) operates at max speed. Your board has about half the specs of mine, so you're in no danger 🙂

678HCV · ‎02-05-2019

I got two M.2 on z390 Strix F MB and (both are PCIE,) and all SSD ports are available so you should be ok.

usernameistoosh · ‎02-05-2019

Ch3vr0n wrote:
You said it yourself when the M.2 sockets are operating in SATA MODE (aka SATA BASED M.2 drives), sata port 2 will be disabled. Since you're using NVME drives that issue is moot. I was wondering the same thing back on my M8F because on 1 page it said even with nvme drives a sata port with be disabled and on another it said no port would be disabled. Hooked up an M.2 nvme drives, all SATA ports were operational.

678HCV wrote:
I got two M.2 on z390 Strix F MB and (both are PCIE,) and all SSD ports are available so you should be ok.

Good to hear. Thanks. The following thread is what largely had me concerned:

https://rog.asus.com/forum/showthread.php?99659-Disabling-SATA-1-if-Using-M-2_1

The main topic starts off with the ports issue, but then moves into the speed issue. Seeing as how my mobo is much newer, I was hoping any potential issues surrounding the above would be worked out by now. I just have to wait about a week before I can test all this out...

pkincy · ‎02-06-2019

Do carefully read the manual as to what speed you must run M.2-2 at. On my XI Hero WiFi and on my Z370-E I must run M.2-2 at X2 not X4, so there is some small speed issue although I don't really see it in benchmarks. I am running 3 NVME drives with the 3rd in a PCIe add on card and have all the SATA ports also occupied.

usernameistoosh · ‎02-07-2019

pkincy wrote:
Do carefully read the manual as to what speed you must run M.2-2 at. On my XI Hero WiFi and on my Z370-E I must run M.2-2 at X2 not X4, so there is some small speed issue although I don't really see it in benchmarks. I am running 3 NVME drives with the 3rd in a PCIe add on card and have all the SATA ports also occupied.

I've read the manual cover-to-cover a few times. It doesn't ever at any one point mention running at x2, or that this is even an option. It states "2 x M.2 ... (both SATA & PCIE 3.0 x 4 modes)". So I know that both can run at x4, the issue being if both running at the same time are x4 or x2+x2. The mobo is a Z390, so like the Z370 it can support up to a maximum of 24 lanes. I just can't find a conclusive statement anywhere that says how many lanes this particular mobo actually does have. That said, it has only one expansion slot that's x16. So there's nothing else to take up lanes. The expansion slot at x16 + the two M.2 slots at x4 each is exactly 24. If there's nothing else needing lanes, then I don't see a reason why those two M.2 slots can't stay at x4 when both are in use.

usernameistoosh · ‎02-12-2019

Just an update on the situation since my parts came in and the rig is all set up and working.

So, I have complete functionality with the SATA6 ports when both M.2 slots are occupied in NVMe mode. Therefore, NVMe will not disable any SATA6 ports. It's exactly as in the manual, your SATA6 port will get disabled only when your M.2 is running in SATA mode.

As for the M.2 speeds, I'm not seeing any BIOS options to change the number of lanes used. So, from what I can tell both M.2 slots are each independently using x4. This makes sense since there's only one PCI-e slot, which is x16. Therefore, x16 + x4 + x4 = x24 max achievable, which is the max supported anyways.

Ch3vr0n · ‎02-13-2019

Which model of nvme SSD's are you using? If samsung's the magician software should be able to tell you exactly what speed they're operating in.

usernameistoosh · ‎02-13-2019

Both 970 EVO, and Magician says PCIe Gen. 3 x 4 for both. So yeah, looks like it is x16 + x4 + x4. I've been using Magician just for the firmware update for my older Samsung drives. Didn't realize it had this info until now! LOL :facepalm:

Ch3vr0n · ‎02-14-2019

Then you're all set, x4 is max speed. If you're not doing so already, make sure u use the samsung nvme driver! Might squeeze out some extra speed.

Mixing M.2 NVMe with SATA