Z690-E Gaming Wifi: Ideal M.2 Drive Placement

[DrSuSE]

Hi there... I just noticed that my GPU only runs at x8, not x16. From what I have researched, it sounds like it must be because of where I have my two m.2 drives installed?

Where should I install these drives so that they don't take away from the GPU bandwidth?

Thanks!

Edit: Just wanted to include that both drives are Firecuda 530s (2TB, M.2 2280-D2).

[DrSuSE]

Continuing to read and try to understand... so it looks like they're in M.2_1 and M.2_2 right now... but SHOULD be in M.2_2 and M.2_3 instead.

If I relocate the drives...

1. Will both M.2 drives still run at their ideal speed? I think this should be yes.
2. Any reason that I cannot move M.2_1 to M.2_2, make it the top entry in boot priority and move M.2_2 to M.2_3? I guess what I am asking is does this have any Windows/OS concerns/considerations?

Then I think my GPU would be at x16.

[RogScott]

If you want a GPU in PCIEX16(G5) to run at x16, you need to avoid using M.2_1. You can use M.2_2, M.2_3, or the included Hypercard without impacting G5.

The Z690-E manual, page vii, states this as follows:
** When M.2_1 is occupied with SSD, PCIEX16(G5) will run x8 mode only."

I put my boot drive in M.2_2. Additional drives can be placed in M.2_3 or on the included hypercard. I placed the hypercard in the bottom slot, PCIEX16(G4), with two drives on it. Note also that the hypercard needs to be in G4 *and* have bios set to support PCIEx16(G4) x4/x4 mode to correctly to support two drives at x4.

[RogScott]

We were both typing at the same time, lol.

Yes, you've got it right in post#2. Use M.2_2 and M.2_3 and the GPU in G5 will run x16, while both M.2 drives will run X4.

As I recall, M.2_2 has direct lanes to cpu, whereas M.2_3 is on the PCH -- so M.2_2 may have a *slight* edge in performance, making it preferable for boot drive. When I tested both, I saw no significant difference, but there might be when the PCH is busier.

[DrSuSE]

RogScott wrote:
We were both typing at the same time, lol.

Yes, you've got it right in post#2. Use M.2_2 and M.2_3 and the GPU in G5 will run x16, while both M.2 drives will run X4.

As I recall, M.2_2 has direct lanes to cpu, whereas M.2_3 is on the PCH -- so M.2_2 may have a *slight* edge in performance, making it preferable for boot drive. When I tested both, I saw no significant difference, but there might be when the PCH is busier.

Thank you a ton for both replies! Much appreciated! Project for tonight!

[DrSuSE]

RogScott wrote:
We were both typing at the same time, lol.

Yes, you've got it right in post#2. Use M.2_2 and M.2_3 and the GPU in G5 will run x16, while both M.2 drives will run X4.

As I recall, M.2_2 has direct lanes to cpu, whereas M.2_3 is on the PCH -- so M.2_2 may have a *slight* edge in performance, making it preferable for boot drive. When I tested both, I saw no significant difference, but there might be when the PCH is busier.

Ok... Bad news, I moved the drives as described, but the GPU is still only x8. It's set to AUTO in the BIOS SA Agent area, should I set it specifically? Should it be Gen5 or Gen4? What else might cause this?

M.2 _1 is empty, _2 and _3 have drives. No hyper card thing.

[DrSuSE]

Just for the sake of being thorough... I re-seated the card after pulling and cleaning it. No change... Still just x8.

I'm stumped.

[RogScott]

I’m stumped too…. I’ve run that exact configuration and got x16. *“Auto” should work.

First suggestion would be to reset bios to “optimized defaults” and see if that changes anything. *What GPU, and how are you checking for x16? *Also, do you have “fast boot” on in bios or windows? *That could cause windows to use the old configuration - so turn those both off and restart, then test again.

[DrSuSE]

RogScott wrote:
I’m stumped too…. I’ve run that exact configuration and got x16. *“Auto� should work.

First suggestion would be to reset bios to “optimized defaults� and see if that changes anything. *What GPU, and how are you checking for x16? *Also, do you have “fast boot� on in bios or windows? *That could cause windows to use the old configuration - so turn those both off and restart, then test again.

No dice, did exactly as you suggested.

I have an MSI 4090 and an EVGA 3090 I'm testing with.

Confirming x8 in the BIOS, GPU-Z, and in the Nvidia control panel.

[RogScott]

Strange... I have a EVGA 3090 FTW3 on my Z690-E, and it's running x16 (as long as M.2_1 is empty). So it should work. Almost sounds like the bios is "stuck" remembering something in M.2_1, but resetting to defaults should have solved that. If it says x8 in bios, then nothing you can do in Windows will fix that.

I vaguely recall some EVGA 3090 x8 problems that were fixed with a vbios -- so an old bios on the 3090 might cause it to run x8. But that shouldn't be an issue with the 4090. So again, that points back to the Z690.

What bios is on your Z690?

I am attaching some screen shots of my settings. Maybe you'll spot something there that's different from yours. If there are other settings / configuration details you want to compare, let me know and I'll try to provide them.

You might also try posting on the "600 & 700 series motherboards" section ( https://rog.asus.com/forum/forumdisplay.php?314 ), as more z690 owners may see your post there and have ideas. There was a LOT of discussion about this last year, so maybe someone there had the same issue and found a solution they can share.