8khz devices and usb ports (rear IO)

[Jason_X]

Hello to all of you! I saw a topic here about devices with a high frequency (2,4,8 khz).

But I have a specific question: what did you mean when you said that high-Hz devices should be inserted into the farthest USB ports?

Did you mean the farthest ones in terms of rear location? Or did you mean as far as possible from the point of view that, for example, I should connect the mouse to the port that goes directly to the processor, and the keyboard to the port that goes to the chipset, and that will be enough?

In other words: for the least input lag (or for the correct work of both devices), is the option suitable for me in which I connect all devices with high Hz to the processor, and the ports will be under each other? (X670E Ace)

Or do I need to look for a motherboard on which I can just connect a mouse to the processor, a keyboard to the chipset, but the ports would be geographically opposite to each other? (something like B650E Carbon or another board with a large (or at least some) physical distance between the processor and chipset ports)

I am attaching 3 photos, the first one X670E Ace - 3 ports under each other, all connected to the processor. Third port - bios flashback.
Second photo - X650E Carbon. Processor ports are located on opposite sides of the network connector
Third photo - Asrock Taichi Lite. A board on which the ports are located as far apart from each other as possible, but not one of them is connected to the processor. Moreover, the extreme ports on the panel, if I understand correctly, may not have enough power for the devices.

My specs now:

Z790 Edge
13900K

My devices: Razer 8khz, Razer Huntsman V2 (8khz), Acer 390Hz monitor, Hyper X Cloud II.

Since my motherboard does not have ports directly to the processor and there is no second slot to the processor either, I connected headphones to the 2.0 ports, and divided the mouse and keyboard into different usb-controllers. Everything seems to be working correctly.

But I still want to assemble an ideal system for high-Hz devices.

[HarryDrews]

Using ports connected directly to the CPU (rather than chipsets) will generally reduce latency.

The topic of that post was suggesting that, while using high polling peripherals (i.e. 8khz mouse w/ 4khz keyboard), the ports used should not be on the same lane/hub. Generally, ports that are adjacent in proximity use a shared lane/hub, which introduces issues with high polling mouse & keyboard combos.. But by using USB ports further from one another, you'll often find that they're not on a shared lane/hub.

Going by physical proximity is just a way of playing the USB port "lottery". Check HWinfo or Device Manager to confirm if you've identified chipset vs CPU direct, or shared/indepdent USB ports.

I hope that makes sense -- and I gladly welcome anyone and everyone to chim in as I think more discussion on this topic is important

[Jason_X]

Using ports connected directly to the CPU (rather than chipsets) will generally reduce latency.

The topic of that post was suggesting that, while using high polling peripherals (i.e. 8khz mouse w/ 4khz keyboard), the ports used should not be on the same lane/hub. Generally, ports that are adjacent in proximity use a shared lane/hub, which introduces issues with high polling mouse & keyboard combos.. But by using USB ports further from one another, you'll often find that they're not on a shared lane/hub.

Going by physical proximity is just a way of playing the USB port "lottery". Check HWinfo or Device Manager to confirm if you've identified chipset vs CPU direct, or shared/indepdent USB ports.

I hope that makes sense -- and I gladly welcome anyone and everyone to chim in as I think more discussion on this topic is important

No, my question was what matters in the end? Is it important to separate high-Hz devices as physically as possible from each other? Or is it important to connect (all) high-Hz devices to the processor, and the remaining devices to the chipset?

For example, on the X670E Ace board, 3 ports are located below each other, in one column. All 3 are connected to the processor.

Returning to my original question, if it is important to separate the ports as far apart physically as possible, then Ace is not suitable for me, because 3 ports, although they all go to the processor, are located close to each other. And this will interfere with the signal and operation of the devices.
If it is important to connect all high-Hz devices to the processor, then Ace is almost ideal, because there is a port for a mouse, there is a port for a keyboard, and 1 more port remains in reserve (for example, for headphones or a USB sound card), plus there is the remaining ports to the chipset.

[HarryDrews]

The answer is - both are important:
1) Directness (reducing chipset jumps) keeps latency low.
2) Minimizing use of one lane allows proper bandwidth throughput for high-polling peripherals.

aaaand...
3) Mouse should be priority.
What most people do is prioritize the mouse by putting it on the USB port directly to the CPU, and (if you don't have another port on a separate lane directly to CPU), putting the keyboard on separate port that goes through chipset. Mice should be priority over keyboard.

[Jason_X]

The answer is - both are important:
1) Directness (reducing chipset jumps) keeps latency low.
2) Minimizing use of one lane allows proper bandwidth throughput for high-polling peripherals.

aaaand...
3) Mouse should be priority.
What most people do is prioritize the mouse by putting it on the USB port directly to the CPU, and (if you don't have another port on a separate lane directly to CPU), putting the keyboard on separate port that goes through chipset. Mice should be priority over keyboard.

That is, if I connect both the mouse and keyboard to the ports that go to the processor, and these ports are next to each other, is this good? In this case, it will be more important that both devices are connected to the processor, right? Than the fact that the ports are close to each other.

[HarryDrews]

The answer is - both are important:
1) Directness (reducing chipset jumps) keeps latency low.
2) Minimizing use of one lane allows proper bandwidth throughput for high-polling peripherals.

aaaand...
3) Mouse should be priority.
What most people do is prioritize the mouse by putting it on the USB port directly to the CPU, and (if you don't have another port on a separate lane directly to CPU), putting the keyboard on separate port that goes through chipset. Mice should be priority over keyboard.

That is, if I connect both the mouse and keyboard to the ports that go to the processor, and these ports are next to each other, is this good? In this case, it will be more important that both devices are connected to the processor, right? Than the fact that the ports are close to each other.

Correct. In fact, most people who have done extensive testing can't identify any change when using adjacent ports (that use the same PCIe lane).. myself included.

I would prioritize connection straight to the CPU, even if you're using two ports next to one another. If you experience absurd latency, it's more than likely a software related issue than anything else.

Here is a great guide for reducing latency and testing your machine:
https://docs.google.com/document/d/1c2- ... mrau4/edit