Z390 DESIGNARE Help

[Melodist]

Greetings,

 

According to the diagrams, when using 2 NVMe SSDs, apparently only 3 Sata Connectors will remain right?

 

If both NVMes are connected, am I still able to hook up another NVMe via the PCIeX4 slot?

[Melodist]

Anybody?

[GabrielFerrazTPU]

2 hours ago, Melodist said:

Anybody?

Hello.

Yes that's exactly right, you'll only have 3 SATA III ports available.

And Yes you can use a separate adaptar, however it might affect the PCI-Express X16(for the graphics card) since the Core i7 and i9 only has 16 PCI-E Lanes.

[Melodist]

5 hours ago, GabrielLP14 said:

Hello.

Yes that's exactly right, you'll only have 3 SATA III ports available.

And Yes you can use a separate adaptar, however it might affect the PCI-Express X16(for the graphics card) since the Core i7 and i9 only has 16 PCI-E Lanes.

But it doesn't say it is taking up the x16s Slot bandwidth, slot number 4, that's what I'm trying to understand.

[GabrielFerrazTPU]

13 hours ago, Melodist said:

But it doesn't say it is taking up the x16s Slot bandwidth, slot number 4, that's what I'm trying to understand.

You need to understand, even it will work, the CPU can handle only 16 lanes, if the GPU is plugged in the first x16 slot, it will work as x16, if you try to do an SLI for example and put a second GPU in the other X16 slot, both of them won't work as x16, but both at x8 speed.

Depending on what slot you plug the X4 card, it might be controlled by the CPU or the Chipset.

[AKBrian]

This board has a bit of an odd party trick in that there is a physical switch that can toggle the last slot (the x4) to utilize the CPU's bandwidth rather than the PCH.

 

In normal operation, the main x16 (physical) slots will be divided up as such:

· x16 / x0 / x4 (PCH)

· x8 / x8 / x4 (PCH)

 

You can, by using the switch to route the lanes to the CPU, also choose one of these three modes for the board's main x16 (physical) slots:

· x16 / x0 / x0 (CPU)

· x8 / x8 / x0 (CPU)

· x8 / x4 / x4 (CPU)

 

The main difference is that in this configuration (slot #3 routed to CPU) the third slot isn't fighting the NVMe M.2 and SATA ports for bandwidth across the DMI link (from PCH to CPU). If you intend to run a third or even fourth NVMe M.2 with an x4 conversion card, this is the mode you want! By necessity, you will be required to run your GPU at x8 - the CPU only provides 16 lanes to divvy up between all three primary slots. By stealing four lanes for the third slot, the first slot will run at x8. Note that even if you are reduced to x8, the speed difference is negligible, on the order of 2-3% slower vs x16 for even an RTX Titan.

 

If you're looking to simply add an extra PCI-E card to get back some SATA connectors due to running dual NVMe M.2 drives (and subsequently losing some onboard SATA ports), the best option is a small x1 PCI-E add-in card like this one. The PCI-E slots all operate through the chipset, over DMI, and do not utilize lanes directly connected to the CPU. This will then let you feed all 16 PCI-E lanes to the top slot for your graphics card, without needing to fiddle with the third x16 (physical) slot at all.

 

It's still confusing, but hopefully that helped to sort of visualize it a bit. There's a post on Level1Techs discussing this feature, which also includes a press image showing a sample configuration utilizing this mode - a workstation with a Quadro and two Intel PCI-E SSDs. Both drives would be able to achieve maximum speed as they are not fighting for bandwidth across the DMI link.

 

Good stuff.