[SOLVED] ASUS Z370 Maximus X Hero- Best Configuration for 4x PCiE NVME Drives?

[hornirl]

Hi,

Just received one of the above mobos, along with an i7-8700K. Trying to kit it out, I've 4x PCIe NVME drives from other systems (varying brands/sizes but example here- all PCIe interface, not SATA) along with some adaptors for PCIe slots. Previously in a Z97 board I had a graphics card running at 8x (lanes) in PCIe x16 slot 1, and an NVME drive using an adaptor running at 8x (lanes) in PCIe slot 2 as a boot drive. My understanding is these slots connect directly to the CPU. I also had another NVME drive with adaptor running at 4x (lanes) in PCIe x16 slot 3, but this I believe is connected to the chipset. So 2x NVMEs in this mobo and I think that's the best possible configuration.

I'd like to repeat this in the ASUS Z370 Maximus X Hero, but I've also got the M2 slots- 2 of them. With 2 NVMEs in PCIe x16 slots (the other PCIe x16 slot has the graphics card), can I put the other 2x NVMEs in the M2 slots?

The manual speaks of some SATA ports being disabled, but I think that's only if SATA NVMEs are in the M2 slots and mine are PCIe. Thanks for any pointers/suggestions here.

 

[Lutfij]

Supports Intel® Smart Response Technology*4
1 x M.2 Socket 3, with M key, type 2242/2260/2280 storage devices support (PCIE 3.0 x 4 mode)*3
Intel® Z370 Chipset :
1 x M.2 Socket 3, with M key, type 2242/2260/2280 storage devices support (SATA & PCIE 3.0 x 4 mode)*2
6 x SATA 6Gb/s port(s)
Support Raid 0, 1, 5, 10
Intel® Optane™ Memory Ready

*2 When the M.2_1 socket is operating in SATA mode, SATA port 1 will be disabled.
*3 When the M.2_2 socket is operating in PCIEX4 mode, SATA ports 5 and 6 will be disabled.

the same is stated in the spec sheet in the manual for the motherboard.

That being said, the 2 M.2 slots on the motherboard can handle 2 out of the 4 SSD's you've generically mentioned. The other two could go onto an adapter which will populate slots PCIEX8_2 and PCIEX4_3 respectively. The GPU will go into PCIEX16_1. Just keep in mind to set the bandwidth for PCIEX4_3 to x4 mode in BIOS otherwise it'll run at x2 speeds.

As always, make sure you've got the latest BIOS version before proceeding to drop in your SSD's.

 

[hornirl]

Thanks a million, this is solution. Just to confirm my understanding here with a couple of extra Qs, and if I had to prioritize placement of NVME drives if I had only 2 instead of 4:

1. PCIEX16_1 and PCIEX16_2 connect directly to CPU, other PCIE slots go through Z370 chip.
2. GPU goes in PCIEX16_1, using x8 lanes (unless it's a GPU that absolutely needs 16 lanes, some way in the future for me).
3. Windows Boot NVME Drive goes in PCIEX16_2 using 8 lanes (it's only wired for 8 anyway) with an adaptor. Going straight to the CPU should make Win OS instrux execute faster, right?
4. PCIEX16_3 can also take an NVME Drive with an adaptor, using 4 lanes with an adaptor- need to change in BIOS to use 4 lanes as it defaults to 2 lanes sharing bandwidth with the last PCIEX1_3 slot. But this goes through the Z370 chip (as do the 3xPCIEX1 slots)., right?

That would seem best use of my PCIE slots, given my current GPU (RTX 2060 Super and @ x8 lanes <1% performance hit).

Moving now to M2 slots, my question would be if I have only 2 NVME drives (and the first (boot drive) goes in PCIE16_2 using the 8 lanes and for the direct CPU link, seems no brainer best option), would it be better to put the 2nd drive in PCIEX16_3 using 4 lanes or in an M2 drive also using 4 lanes and PCIe? They both go to the Z370 chip at same PCIe transfer rate, so is it better to put in a PCIE or M2 slot (better air flow/heat dissipation? Or does the adapter to put on a PCIe slot degrade performance in any meaningful way that would make M2 best)?

Really this last Q is a generic is M2 PCIe @ 4 lanes better than using PCIEX16_3 PCIe slot @ 4 lanes given they both go through the Z370 (or other) chip, and for any particular reason(s)?

DMI 3.0 seems something of s bottleneck to all this, but it applies across the board to everything going through the Z370 chip, nothing we can do about that.

 

[Lutfij]

if I had only 2 instead of 4:
NVMe's can't take advantage of 8 lanes, they're bound to 4. You're overthinking this if you're going to be working with 2 M.2 SSD's as opposed to 4. The board has 2 physical M.2 SSD slots, negating the need for adapters, again, this if you're going to be working with 2 SSD's and not 4.

 

[hornirl]

if I had only 2 instead of 4:
NVMe's can't take advantage of 8 lanes, they're bound to 4. You're overthinking this if you're going to be working with 2 M.2 SSD's as opposed to 4. The board has 2 physical M.2 SSD slots, negating the need for adapters, again, this if you're going to be working with 2 SSD's and not 4.

Ah, big error on my part, these NVMEs can only use 4 lanes, so the one in PCIE16_2 is only using 4 lanes out of an available 8. It's only benefit being there- if it is one- is that it's directly connected to the CPU as a Win boot drive, whereas the M2 slots go through the Z370 chip first.

I already have the adapters so only remaining Q is where is best for the 2nd NVME, PCIEX16_3 using 4 lanes or in an M2 drive also using 4 lanes and PCIe (better air flow/heat dissipation in PCIe slot? Or does the adapter to put on a PCIe slot degrade performance in any meaningful way that would make M2 best)?

Thanks for your help (and patience!).