Jesseinsf wrote:
The three X1 slots use the PCH PCIe lanes which is 24 PCIe lanes. However those PCIe lanes get crunched down to 4 lanes going to the processor through DMI 3.0. The three X16 PCIe slots are directly connected to the processor and share the 16 PCIe lanes. The bottom X16 slot only runs at 4X only. Your Sound card should be plugged in to a X1 slot which uses the PCH and will not affect you Graphics card. Same thing goes for the M.2. You should plug in the PCIe M.2 module in to the M.2_2 Socket 3 not the M.2_1 Socket 3.

Now a word of advice, for maximum throughput, you don't want to connect to much PCIe x1 cards and more than one M.2 PCIe SSD because the 24 PCIe lanes that the PCH chipset uses gets crunched down to 4 lanes that are directly connected to the processor (DMI 3.0). There is not much bandwidth left after your Samsung M.2 PCIe SSD and AE-9 are connected. Remember the PCH Chipset uses DMI 3.0 to directly connect to the processor which only has 4 PCIe lanes which has a bandwidth of 3.94 GB/s. My Samsung 1TB 970 Pro used up to (almost) 3.5 GB/s. As you can see I don't have much bandwidth left. Everything except the RAM and graphics card shares the DMI 3.0 bandwidth. All USB interfaces, Wireless and wired networking, SATA devices, Bluetooth devices and Onboard Audio All go through the PCH chipset. Connecting to many things will cause the PCH chipset to work allot more as it has to prioritize more data thus slow things down a bit.

One more piece of advice. Disable anything that you don't use in the BIOS. For me I disable all wired connection and onboard audio. This should keep your system going smoothly.

Hope this helps

bamajon1974 wrote:
Thank you for your reply. I currently have an M.2. SSD in the M.2. socket right above the PCIEX16 slot 1, I have the graphics card in PCIEX16_1 slot, and sound card in the PCIEX1_2 slot. PCIEx1_1, PCIEX1_3, PCIEX16_2 and PCIEX16_3 slots are empty, with labels according to the ROG STRIX Z390E manual.
Is this configuration ok?

I want to add a USB 3.1 Gen 1 PCIEx expansion card to the MoBo as well. Which PCIE slot should it be plugged in? Or should I not install it and save on bandwith?

I have external sound and graphics cards but the motherboard has internal Intel Graphics and Realtek Sound that I don't use. Additionally, my computer is connected to a network through ethernet cord and I don't use the wireless. Should all three of these onboard devices be disabled in the BIOSUEFI then?

Thanks!

Jesseinsf wrote:
Your Graphics card and sound card are in the correct slot types.
If you want the graphics card to stay at 16X then only use the smaller slots for any other cards which will use the PCH Chipset bandwidth instead.
The reason why they have less USB ports on your Motherboard was to give that bandwidth to PCIe X1 cards. If the USB card you have is a X4 card then you will have to plug it in to the X16 slot which will make your graphics card go down to 8X. If it is a X1 card then plug it in to the X1 slot.
If I were you then I would get a powered USB 3.1 gen 2 hub which will utilize the port's 10GB/s speed.

bamajon1974 wrote:
This is the USB expansion card I bought. It fits into a PCIe 1 slot so I should be ok, right?

https://www.amazon.com/gp/product/B07Z34BJYH?psc=1

Tiergrade Superspeed 7 Ports PCI-E to USB 3.0 Expasion Card with 15-Pin SATA Power Connector

I actually posted another thread about which peripherals are better suited for powered USB hubs vs. connecting directly to the motherboard.

https://rog.asus.com/forum/showthread.php?117940-Peripherals-can-be-connected-to-USB-ports-on-the-ba...

Jesseinsf wrote:
That should be fine. Keeps in mind that this card can only transfer 5GB/s. All USB ports on this card will share the 5GB/s bandwidth. If you are using all ports on this card then you will not get the full USB 3.1 gen one specification speeds (which is 5GB/s). if I were you I'd get a Gen 2 hub that plugs in to your Gen 2 USB port which is backward compatible and will give you faster speeds than the PCIe card will.

Jesseinsf wrote:
That should be fine. Keeps in mind that this card can only transfer 5GB/s. All USB ports on this card will share the 5GB/s bandwidth. If you are using all ports on this card then you will not get the full USB 3.1 gen one specification speeds (which is 5GB/s). if I were you I'd get a Gen 2 hub that plugs in to your Gen 2 USB port which is backward compatible and will give you faster speeds than the PCIe card will.