Please help me understanding pcie lanes. (Asrock X570m PRO - Ryzen 5 PRO 4650G)!!

[Oedzesg]

Hallo all,

Unfortunately, AMD does not provide all the information about the PCIE Lanes of the Ryzen 5 PRO 4650G on their site.

I use this CPU in combination with an ASROCK X570M PRO.
If I understand correctly, pcie slot_1 and slot_3 run on X16 when used alone.

if both slots are in use, slot_3 will still have x4 available and slot_1 will continue to run at x16.
These PCIE x16 slots are directly connected to the CPU.

My mobo has 2 m.2 connections. 1 of these is also directly connected to the CPU via 4 lanes.

Maybe a stupid question but I can't find anywhere in the documentation which of the 2?

In addition, the CPU communicates with the chipset through 4 lanes.
The 2nd m.2 slot is connected via this chipset and also the 8 sata ports and the last PCIEx1 port.

If I have also understood this correctly, not all 8 sata connections are available anymore when I use the 2nd m.2 slot.
Again I can't find anywhere which ports are blocked.

As indicated, not all information about the number of PCIE lanes is listed on AMD's site, but I read somewhere that 20 lanes are available.

In my current setup:

* Silverstone CS381 case.
* All 8 drives connected to the backplane via LSI HABA card.
* m.2 120 gbit as boot drive.

Since I only use this setup as a nas, this works fine.

What I would like:

* adding a 2 port 10gbe network card in the 2nd X16 slot.
So it runs at 3.0x4 which is sufficient as far as I've read

* Add 2nd nvme for temporary files (e.g. the
extracting downloaded files via NZBGet).

* Add 2 internal SSD through the sata ports for using
Docker.

My simple mind then tells me that this won't work because I don't have enough lanes available from my CPU.

PCIE slot_1 = 16 lanes
PCIE slot_2 = 4 lanes
NVME_1 = 4 lanes
Motherboard connection to the chipset = 4 lanes

This is a total of 28 lanes which I do not have available.

Am I completely missing the point and are you laughing at me? Or is it correct as I think?

I hope there is someone who can give me a clear explanation.

Thank you very much!

 

[Etorix]

Unfortunately, AMD does not provide all the information about the PCIE Lanes of the Ryzen 5 PRO 4650G on their site.

Or the combination of a long-lasting socket, which has seen many different generations of CPUs with different capabilities, the use of code names to designate these generations rather than a straightforward numbering scheme, AND a consumer-grade motherboard whose documentation lacks a block diagram, makes it unnecessarily complex.

Let's try. Ryzen 5 PRO 4650G is "Renoir".

I use this CPU in combination with an ASROCK X570M PRO.

Specifications
Renoir can always use both PCIe slots 1 and 3 at x16 and x4.

My mobo has 2 m.2 connections. 1 of these is also directly connected to the CPU via 4 lanes.

Maybe a stupid question but I can't find anywhere in the documentation which of the 2?

Ask the manufacturer's support for a block diagram.

In addition, the CPU communicates with the chipset through 4 lanes.
The 2nd m.2 slot is connected via this chipset and also the 8 sata ports and the last PCIEx1 port.

So you actually know?

If I have also understood this correctly, not all 8 sata connections are available anymore when I use the 2nd m.2 slot.

Not sure where you have seen that. Typically a PCH SATA lane may be shared between a SATA port and a M.2 slot but NVMe is not affected: If the M.2 slot holds a NVMe drive, all SATA ports are usable.

As indicated, not all information about the number of PCIE lanes is listed on AMD's site, but I read somewhere that 20 lanes are available.

x16 + x4 for the two PCIe slots (where x16/x0 or x8/x8 plus x4 for a M.2 slot could have been a better choice)
downstream lanes for the PCH are typically not counted as "available"

Both M.2 slots should then hang from the PCH.

 

[Oedzesg]

 

[Oedzesg]

Thnx!

so it looks like lots of devices share the 4 lanes between de cpu and the chipset.