Maximus Hero 7 Will Not Post w/M.2 enabled in SLI

[spindrift61]

Hello, anybody know why my Hero 7 MB will not post if I enable M.2 SSD? I am running MSI GTX 980 in SLI and runs without problems. I attempted to "reinstall" a Samsung 950PRO M.2 that I had in the system before experiencing other problems...unrelated to this problem. Has been over a year and want to reinstall my M.2. I have (always have had) 2 other SSD's in this system. An Intel 500GB and a Seagate 1TB. Had other issues I resolved in past unrelated to this one and the reason I took out the M.2 and started to use the other SSD's. The other issues mostly due to faulty PS (Corsair AXI 1200). The system has a I7-4790 CPU, Corsair AXI 1500, 32GB RAM and CPU and 2 GPU's cooled by water. It is an old system by today's standards I realize, but it is what I have at the moment and I use it to power multiple monitors (7) for personal trading of stocks. I have gone into UEFI and enabled M.2 and will not post unless I go back into UEFI and set M.2 to disable. I am not trying to boot from my M.2 and using one of my SSD's that has WIN 10 on it. So the boot sequence is not the problem. I sure would appreciate any help

[Nate152]

Hi spindrift61

Welcome to the ROG forum.

The i7-4790 has 16 pcie lanes.

The M.2 slot supports pcie mode and uses x2 pcie lanes from the cpu. With two Nvidia gpu's running at x8 x8, there is nothing left for the M.2 slot.

[spindrift61]

Nate152 wrote:
Hi spindrift61

Welcome to the ROG forum.

The i7-4790 has 16 pcie lanes.

The M.2 slot supports pcie mode and uses x2 pcie lanes from the cpu. With two Nvidia gpu's running at x8 x8, there is nothing left for the M.2 slot.

Thanks, something I did not know. I would have answered sooner, however wanted to research your comment to get a better understanding of what you were referring to. I now understand the I7-4790 only supports 16 lanes and the GPU's I have each require 8 for a total of 16 lanes, which is the maximum the CPU supports. I also went to Samsung's site and my M.2 is an NVMe and is requires 4 lanes. I researched in UEFI if I could set one or both GPU's to 4x to be able to share lane resources with the M.2 SSD but did not find this setting. Is there a method that would allow this in UEFI? As stated in my post, I once had this M.2 installed although I am unsure if I was running SLI. As to the reason I would like this M.2 is because #1 I have it, #2 I have the opinion it "may be " faster (from what I have read) and lastly after I built the system I believe it was working initially (although it appears with the limited lanes supported I may be incorrect). I appreciate you taking the time to converse with me on the subject. I rarely reach out for assistance and normally I get my answers by researching the heck out of the subject and spending an exorbitant amount of time. Believe I have already beaten that dead horse and need some expert advise (something I do not have on the subject). Thanks

[Nate152]

Nvidia gpu's need x8 pcie lanes to work, if you had AMD gpu's this could be possible as AMD gpu's need only x4 pcie lanes to work.

I run sli myself and I like the extra performance in games that support sli.

My suggestion would be to keep sli and use a sata ssd.

[spindrift61]

Nate152 wrote:
Nvidia gpu's need x8 pcie lanes to work, if you had AMD gpu's this could be possible as AMD gpu's need only x4 pcie lanes to work.

I run sli myself and I like the extra performance in games that support sli.

My suggestion would be to keep sli and use a sata ssd.

Thanks for your help Nate. I am unable to remember why I had the m.2 installed or if I was in fact reading off it. For all I remember it was never set up. I did have it installed and I was running my GPU's in SLI from the very beginning. However, my operating system could never have been on it and still have SLI after what I have learned from you. The system I have is old by todays standards (build date 2018). I will continue to use my GPU's as I need the available outputs they have to run my monitors more than I need speed. I do not take someone's knowledge for granted and you have supplied me with an answer, albeit not the one I was looking for. Many Thanks.

[Nate152]

You're welcome,

There is another solution.

You could get an M.2 NVMe adapter for your M.2 NVMe ssd and install it in the third pcie x16 (black) slot, this slot runs at x4 off the pch/chipset.

As for setting it up as a boot drive I'm unsure of.

Something like this.

https://www.newegg.com/riitop-model-ngftpce-bk-pci-express-controller-card/p/17Z-0061-00018?Descript...

[spindrift61]

Hi Nate and thanks for this option as well. I did not realize you posted another comment or would have answered sooner. I am not sure if that would help as it would run in 4x where as my GPU's run at 8x. But hold a second...I came to ask advise in expectation (hope) you would see my new comment on an alternative use of the Samsung 950 Pro NVMe, since I already have it. If not mistaken I paid a whopping $499 for it and sitting here unutilized.

The advise I was to ask is if I could turn on and off 1 of my GPU's randomly when I needed to run a task on the M.2, but still keep all 3 physically connected. Either by windows or UEFI. The scenario I require this for is for cloning, imaging and back up to the M.2. I do not have an external SSD (or Cloud software) currently and thus no means to compete those tasks. A quick note, I then re-read your comment and noticed you wrote this 3rd slot is PCH controlled, not something I realized.

I am running into this exact scenario as we speak because I would like to have a dual operating system. I have windows 10 on one SSD and Ubuntu (for privacy) on another. A day or two ago I loaded Ubuntu on my 2nd SSD and installed a private email service on it. I now have no back up of either OS. I am not asking for advise on this dual operating system or wanting you to waste your time to set up a complicated system to perform this. Simply (well maybe for you not me) is can I have 2 GPU's and M.2 physically installed and when I need to back up my system, disable 1 of the GPU's and use the M.2. Thus utilizing only 4 out of the 8 lanes of the disabled GPU. I should also add my GPU's are water cooled and the reason I can not take one physically out to do this.

Lastly I have tried to perform this before reaching out to you and this community and have failed. It appears once a GPU card is inserted, whether enabled or disabled, the system recognizes it is installed and those lanes are unavailable to use. I hoping I am wrong but it just could be my asus hero 7 board does not allow this. Hope I have not complicated my query as I often do. Thanks to anyone that wants to comment.

[Nate152]

The only way I know to disable the pcie slots is on the Maximus Extreme motherboards with the dip switches.

You actually have a total of 20 pcie lanes, 16 from the cpu and 4 from the chipset. You could use the third pcie x16 slot which runs at x4 without affecting your gpu's.