Intel Core i7-7820X - PCIe lanes usage

[LukaKitty]

~ Topic Introduction ~

Quite recently, I've been running into a few audio issues, and it's been bothering me. Probably doesn't help I use 2 sound systems for the same audio stream, but regardless.

I've been interested in buying a PCIe x1 sound card to fix some of those issues, and have a bit more flexibility in general, like actually having a TOSLINK-in port.

But the main thing I'm wondering about, is how many "lanes" am I using on my CPU currently? I'm not a computer genius, so I'm not sure.

 

 

~ Currently Installed Parts ~

I've been called 'strange' for the parts I use, but here's some of them, in which I would assume uses PCIe lanes.

 - MSI GeForce GTX 1070 Aero GB OC (PCIe 3.0 x16)

 - AverMedia Live Gamer Lite HD (PCIe 3.0 x1)

 - Samsung 960 EVO NVMe SSD (M.2)

 - Western Digital M.2 SATA SSD (M.2)

 - X299 Chipset

 

From what I heard, Samsung's 960 EVO and PRO series NVMe SSD runs on a PCIe 3.0 x4 interface through the M.2 slot, if I'm not mistaken.

I'd assume I use 21 PCIe lanes or something, but I can't tell for sure. Kind of feel like an idiot for thinking I use that much, but I honestly have no idea. ;w;

 

 

~ Comments ~

So I'm asking you, the community. How many PCIe lanes am I using? Because, again, I have no idea.

Realizing I may or may not sound like an idiot for posting this, I felt like asking regardless.

 

If anyone has an idea, or even know, please inform me.

 

 

 

~ Recap ~

Please don't approach me with a wall of text just because this post is related to a sound card, in 2018. >-<

I'm mostly concerned about my PCIe lane usage, based off from what I currently use.

Thanks in advance for those who understand. ^^;

[Cereal5]

GPU is 16, 960 Evo is 4, AverMedia thing is 1, and the WD SSD uses the SATA bus, so yeah 21. And don't forget you get 4 lanes from the chipset.

[NelizMastr]

Graphics: 16

Capture: 1

SSDs: 4 for the NVMe 0 for SATA

-----------------

21

 

Your CPU itself has 28 lanes, and the chipset also has a few to hand out. The chipset often controls the x1 slots and one or more of the m.2 slots. If you theoretically ran out of lanes, the GPU would go down first to operate in 8x mode, so there's no need to worry about that.

[SpaceGhostC2C]

It won't matter much for the sound card, since any x1 slot is probably wired through the chipset anyway, and from there it takes the (x4 I assume) fixed connection to the CPU. You are not going to connect it directly to the CPU, but through the "PCIe switch", regardless of how many are used (unless you put the sound card in one of the x16 slots).

 

Now, if you are still interested in how many direct lanes to the CPU are currently in use, it will depend on your motherboard's layout and what you've plugged where. I'm afraid just knowing it is an X299 motherboard won't be enough.

[LukaKitty]

4 hours ago, NelizMastr said:

Graphics: 16

Capture: 1

SSDs: 4 for the NVMe 0 for SATA

-----------------

21

 

Your CPU itself has 28 lanes, and the chipset also has a few to hand out. The chipset often controls the x1 slots and one or more of the m.2 slots. If you theoretically ran out of lanes, the GPU would go down first to operate in 8x mode, so there's no need to worry about that.

So even if I occupy 5 SATA-600 ports, no PCIe lanes are in use, right? ^^;

[LukaKitty]

4 hours ago, SpaceGhostC2C said:

It won't matter much for the sound card, since any x1 slot is probably wired through the chipset anyway, and from there it takes the (x4 I assume) fixed connection to the CPU. You are not going to connect it directly to the CPU, but through the "PCIe switch", regardless of how many are used (unless you put the sound card in one of the x16 slots).

 

Now, if you are still interested in how many direct lanes to the CPU are currently in use, it will depend on your motherboard's layout and what you've plugged where. I'm afraid just knowing it is an X299 motherboard won't be enough.

The motherboard I use specifically, is a MSI X299 SLI PLUS. Got 7 PCIe slots, and only 2 of them are PCIe 3.0 x1. However, one of those x1 lanes are blocked by the GPU.

[LukaKitty]

4 hours ago, Cereal5 said:

GPU is 16, 960 Evo is 4, AverMedia thing is 1, and the WD SSD uses the SATA bus, so yeah 21. And don't forget you get 4 lanes from the chipset.

So theoretically, I've got 32 PCIe lanes I can essentially use then, thanks to the chipset? Or at least that would be my assumption if I were to add the CPU lanes with the chipset ones.

[SpaceGhostC2C]

8 minutes ago, Crinklekitty said:

The motherboard I use specifically, is a MSI X299 SLI PLUS. Got 7 PCIe slots, and only 2 of them are PCIe 3.0 x1. However, one of those x1 lanes are blocked by the GPU.

Page 22 of the manual contains the relevant diagram. Three x16 (physically) PCIe slots are connected directly to the CPU using its 18 PCIe lanes. Everything else goes to the chipset, which in turns connects to the CPU with a bandwidth equivalent to 4 PCIe lanes.

That means that, currently, your GPU is using 16 out of 28 direct lanes, while your M.2 SSDs and the capture card (assuming it's on one of the x1 slots) share the x4 connection through the chipset (plus USB, LAN, and any SATA drive if you have one).

Page 32 further clarifies which slot is connected how. Since you are heavily using the PCH lanes (if you somehow loaded all the devices currently connected through it, you could not provide full bandwidth to all of them - the PCIe SSD alone can theoretically use up all the bandwidth), I would recommend connecting the most bandwidth-hungry x1 card (or even better, both) to an x16 slot wired directly to the CPU, since that won't interfere with your GPU running at x16 anyway, and it would avoid potential congestion at the chipset. 

 

The manual is your friend  

[SpaceGhostC2C]

19 minutes ago, Crinklekitty said:

So theoretically, I've got 32 PCIe lanes I can essentially use then, thanks to the chipset? Or at least that would be my assumption if I were to add the CPU lanes with the chipset ones.

To be precise, there are 28 PCIe lanes connected to three physically x16 slots, that will run at x16/x8/x4 maximum with your CPU.

 

Then there is a DMI 3.0 connection, with a bandwidth equivalent to 4 PCIe lanes, to a PCH chip. That PCH chip is connected to the x1 slots, the remaining (physically) x16 slot, LAN, SATA ports, M.2 ports, etc. So, you have kind of 4 more lanes there, but those are shared between everything that connects through the PCH. The PCH acts as a switch, so any device can use up to the equivalent of 4 lanes if no other device is using them, but if more than one device connected through the PCH is asking for bandwidth, they'll get less than x4 equivalent.

That may happen even if you have unused "CPU lanes", since those are available only to devices installed in the relevant PCIe slots, and cannot be shifted to the PCH.

[LukaKitty]

6 minutes ago, SpaceGhostC2C said:

To be precise, there are 28 PCIe lanes connected to three physically x16 slots, that will run at x16/x8/x4 maximum with your CPU.

 

Then there is a DMI 3.0 connection, with a bandwidth equivalent to 4 PCIe lanes, to a PCH chip. That PCH chip is connected to the x1 slots, the remaining (physically) x16 slot, LAN, SATA ports, M.2 ports, etc. So, you have kind of 4 more lanes there, but those are shared between everything that connects through the PCH. The PCH acts as a switch, so any device can use up to the equivalent of 4 lanes if no other device is using them, but if more than one device connected through the PCH is asking for bandwidth, they'll get less than x4 equivalent.

That may happen even if you have unused "CPU lanes", since those are available only to devices installed in the relevant PCIe slots, and cannot be shifted to the PCH.

So... essentially, everything else I've connected, like SATA, M.2, and so on uses a "shared" bandwidth that the chipset provides, or have I mistaken?

Also, I mainly read the manual when setting up certain things, or attempting to troubleshoot anything on it, providing if something happened.

 

Sorry to sound dumb like this, but I appreciate the research.

[SpaceGhostC2C]

4 minutes ago, Crinklekitty said:

So... essentially, everything else I've connected, like SATA, M.2, and so on uses a "shared" bandwidth that the chipset provides, or have I mistaken?

Yes, that is correct.

 

4 minutes ago, Crinklekitty said:

Also, I mainly read the manual when setting up certain things, or attempting to troubleshoot anything on it, providing if something happened.

That's the thing, once we set up a system we eventually forget the manual even exists  But when it's time to set something up again, like a new add-in card, it's good to be reminded of it as the main source of information  

 

4 minutes ago, Crinklekitty said:

Sorry to sound dumb like this

A question is a question, is someone doesn't like it they can just not answer it.