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Is 4x GPU with a Samsung m.2 NVMe drive supported?

slp_pleh
Level 7
Hello,

I have an Asus Rampage V edition 10 board with an Intel Core i7-6850K (40 pcie lanes), four (4) Nvidia 1080 GTX FE GPUs, and a Samsung 950 pro m.2 NVMe flash drive.

When I boot the system up on an SSD disk (NOT on m.2), the pcie slots negotiate to 16/8/8/8 and it works fine.

When I boot the system from the m.2 NVMe drive, the pcie slots negotiate to 8/8/8/8 but the system will not detect the m.2 flash drive.

The user manual, on page ix it states:

40-LANE CPU:
- In 4-Way con guration, if the PCIEX16/X8_1 is used in x16 mode, both U.2 and M.2 ports will be disabled.


So it seems I've hit a bug, or I need to adjust a setting in the BIOS.

Does anyone have any suggestions? The Asus tech support person I spoke with said he would open up a ticket (after I asked him to) with their engineering team but I haven't heard back in almost a week. He seemed to think this wasn't supported but I got the feeling he just wanted to get off the call with me.

Thanks for any help!
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30 REPLIES 30

Menthol
Level 14
No it's not, when you use 4 GPU's there are no more pcie lanes left for NVME drive

Brighttail
Level 11
The M.2 shares bandwidth also with the fourth PCI-e Slot. So if all four PCI-e slots are occupied you'll get 16,8,8,8 but U.2 and M.2 are disabled.

Why would you have four 1080s anyway? I hope it isn't for gaming but something useful like autocad or something cause otherwise 4 of them will kill your FPS.
Panteks Enthoo Elite / Asus x299 Rampage VI Extreme / Intel I9-7900X / Corsair Dominator RGB 3200MHz

MSI GTX 1080 TI / 2x Intel 900p / Samsung 970 Pro 512GB

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Corsair AX 1200i / Corsair Platinum K95 / Asus Chakram

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Korth
Level 14
@Brighttail
Four 1080s will kill fps? I can understand diminishing returns, most games do not implement SLI particularly well so multi-GPU won't scale very well, but isn't 4-SLI still going to outperform 3-SLI, isn't 3-SLI still going to outperform 2-SLI?

Agreed, four GTX1080 cards seems quite wasteful, awful bang for the buck. A very expensive way to (possibly) get a tiny fps bump vs two GTX1080 cards. They might be great for multi-display at high resolutions. They might be great for GPGPU work (like CAD stuff) to a point, though workstation (or Titan) cards with proper DPFP capabilities would generally be a better (and possibly cheaper) choice.

The R5E doesn't allow 4-SLI in x8/x8/x8/x8 configuration? Never tried, lol I just have 2-SLI x16/x16 with x8 PhysX when gaming.

The X99 chipset can support 5-GPU x8/x8/x8/x8/x8 ... or so the specs say ... few X99 mobos have enough PCIe slots and I've never heard of a 5-SLI or 5-CF setup, NVIDIA and AMD can only count to four. I suppose 5-GPU support is intended for workstation GPU stuff, though I think anyone who needs that much GPGPU density in a single machine would be better off running a mobo with a dedicated server chipset (like the C612).
"All opinions are not equal. Some are a very great deal more robust, sophisticated and well supported in logic and argument than others." - Douglas Adams

[/Korth]

Korth wrote:
@Brighttail
Four 1080s will kill fps? I can understand diminishing returns, most games do not implement SLI particularly well so multi-GPU won't scale very well, but isn't 4-SLI still going to outperform 3-SLI, isn't 3-SLI still going to outperform 2-SLI?

Agreed, four GTX1080 cards seems quite wasteful, awful bang for the buck. A very expensive way to (possibly) get a tiny fps bump vs two GTX1080 cards. They might be great for multi-display at high resolutions. They might be great for GPGPU work (like CAD stuff) to a point, though workstation (or Titan) cards with proper DPFP capabilities would generally be a better (and possibly cheaper) choice.

The R5E doesn't allow 4-SLI in x8/x8/x8/x8 configuration? Never tried, lol I just have 2-SLI x16/x16 with x8 PhysX when gaming.

The X99 chipset can support 5-GPU x8/x8/x8/x8/x8 ... or so the specs say ... few X99 mobos have enough PCIe slots and I've never heard of a 5-SLI or 5-CF setup, NVIDIA and AMD can only count to four. I suppose 5-GPU support is intended for workstation GPU stuff, though I think anyone who needs that much GPGPU density in a single machine would be better off running a mobo with a dedicated server chipset (like the C612).


In the case of 1080s, if you just look around the web you will find that for games and such, more than two 1080s actually provides either WORSE performance or the games out here simply ignore anything more than two. There has been multiple testing on this and aside from benchmarking, where the programs can actually use all four, there are literally like no games and very few programs out there that can use more than 2 1080s. In fact there are several programs that won't boot if there are more than 2. This is one of the main reasons that Nvidia doesn't really support anything more than dual SLI.

The R5E10 doesn't support 4 gpu + an m.2 drive in the m.2 slot. The M.2 shares bandwidth/IRQ with that fourth PCI-e slot, so if it is occupied, the m.2 is disabled. It even says so in the manual. The only Asus mB that can support 5way SLI is the Workstation series of the x99.

Anyway the question posed here was why wasn't his m.2 working, I answered that. My comment on 4 way SLI with 1080s was an opinion based off on the reviews/videos of the 1080 in SLI available on the internet.
Panteks Enthoo Elite / Asus x299 Rampage VI Extreme / Intel I9-7900X / Corsair Dominator RGB 3200MHz

MSI GTX 1080 TI / 2x Intel 900p / Samsung 970 Pro 512GB

Samsung 850 PRO 512GB / Western Digital Gold 8TB HD

Corsair AX 1200i / Corsair Platinum K95 / Asus Chakram

Acer XB321HK 4k, IPS, G-sync Monitor / Water Cooled / Asus G571JT Laptop

FireRx
Level 11
totally agree Brightail. It's just not necessary other than e-peening. 🙂
Intel Core i9 103900KS
Asus Maximus Z790 Extreme [bios 1801]
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Menthol
Level 14
Maybe he has a use other than sli for gaming, but if he is there are a couple posts around the net explaining how to create your own profiles, also there are only a couple 3-4way sli bridges that will work on Pascal cards, the EVGA and MSI LED bridges, currently there are only 2 way HB bridges available, I had to go to ebay to find bridges to use 3 and 4 way with Titan X Pascal cards, a 1500 watt power supply is minimum, dual is better as a lot of current can be used when under load
There are many concessions and a lot of effort to make 3 and 4 way sli to work these days as Nvidia no longer supports it except in 3DMark benchmark on Windows 10

This is a password cracker actually, not for gaming (it gets about 100 billion md5 hashes per second).

With the m.2 installed the pcie slots set themselves to 8/8/8/8, that would only be 32 lanes, so why shouldn't the m.2 work? Password cracking doesn't need high speed slots anyway, so x8 is fine. I tried to hard set the slot but I don't see any options for that.

Brighttail
Level 11
Once again, if you actually read the user manual, it says:

"The PCIEX8_4 slot shares bandwidth with M.2 and U.2"

This means that if the fourth PCIE slot is in use, the m.2 slot is turned off. It has NOTHING to do with the number of lanes. It has everything to do with how the motherboard shares the resources available. Just like on the motherboards with Sata-express, if you used one of the PCI-e lanes it would turn off this option and even turn off a couple of SATA ports.
Panteks Enthoo Elite / Asus x299 Rampage VI Extreme / Intel I9-7900X / Corsair Dominator RGB 3200MHz

MSI GTX 1080 TI / 2x Intel 900p / Samsung 970 Pro 512GB

Samsung 850 PRO 512GB / Western Digital Gold 8TB HD

Corsair AX 1200i / Corsair Platinum K95 / Asus Chakram

Acer XB321HK 4k, IPS, G-sync Monitor / Water Cooled / Asus G571JT Laptop

Brighttail wrote:
Once again, if you actually read the user manual, it says:

"The PCIEX8_4 slot shares bandwidth with M.2 and U.2"

This means that if the fourth PCIE slot is in use, the m.2 slot is turned off. It has NOTHING to do with the number of lanes. It has everything to do with how the motherboard shares the resources available. Just like on the motherboards with Sata-express, if you used one of the PCI-e lanes it would turn off this option and even turn off a couple of SATA ports.


I did read the manual, very closely. You are referring to the asterisk that is pointed out in 28 lane CPUs.

See the rest of the section:

4 x PCIe 3.0 x16 slots (supports x16, x16/x16, x16/x8/x8, x16/x8/x8/x8 or x8/x8/x8/x8 mode with 40-LANE CPU; x16, x16/x8 or x8/x8/x8 mode with 28-LANE CPU)* [CPU] <--where they point out the line you were referring to.
1 x PCIe 2.0 x4 slot** [PCH] 1 x PCIe 2.0 x1 slot [PCH]
40-LANE CPU:
- In 4-Way configuration, if the PCIEX16/X8_1 is used in x16 mode, both U.2 and M.2 ports will be disabled.
28-LANE CPU:
- In 3-Way confutation, U.2 port will be disabled.
- By default, U.2 port is disabled for other configurations. To activate it, please go to BIOS > Advanced > Onboard Device Configuration > PCIEX8_2 PCIEX8_4 and U.2 M.2 Configuration.
* The PCIEX8_4 slot shares bandwidth with M.2 and U.2.
** The PCIEX4_1 slot shares bandwidth with front USB3_34 ports and back USB3.1_EC1_EA2 ports.
If a X2 device is connected to the PCIEx4_1 slot, the front USB3_34 ports will be disabled.
If a X4 or higher device is connected to the PCIEx4_1 slot, both front USB3_34 and back USB3.1_EC1_EA2 ports will be disabled.


The line that says "- In 4-Way configuration, if the PCIEX16/X8_1 is used in x16 mode, both U.2 and M.2 ports will be disabled."

Leads me to believe it should work since that slot is used in x8 mode when the drive is installed.