AM5 x670 Motherboards That Don't Drop PCIe from x16 When M.2 Populated?

[Ravenholm]

No, it is not possible.

The lane sharing is hard wired, so the gen is not relevant.

fiddlesticks

The reason it shares lanes with the GPU is because they offer 3x PCI-E 5.0 M.2 slots, if you wanted to run 4x M.2 with no impact then you would have needed a board that only has 2x PCI-E 5.0 M.2 slots.

Yep, my fault. Had to do my homework before purchasing relatively heavy priced motherboard.

I think you might be able to do this by placing an expansion card for 1x M.2 slot, in the third full-length PCI-Express slot at the bottom of the board. (And leave M.2 slot 3 empty)

To buy THIS or similar product and put it in PCI-E_3 slot at the bottom? It looks like that 3rd slot is x4 Gen4 and it had nothing to do with PCI Gen5 lanes from CPU.

 

[Tetras]

To buy THIS or similar product

It looks like that is only 1 lane which would throttle your SSD, you want a 4 lane adapter.

It looks like that 3rd slot is x4 Gen4 and it had nothing to do with PCI Gen5 lanes from CPU.

Yep! From what I can see, you can use that slot freely without worrying about anything else.

 

[Ravenholm]

It looks like that is only 1 lane which would throttle your SSD, you want a 4 lane adapter.

Sorry, wrong link I pasted. I meant THIS one.

Yep! From what I can see, you can use that slot freely without worrying about anything else.

Great. I am ordering it. 970 Evo Plus goes in it and KC3000s will go into 1, 2 and 4 Thank you, kind sir

 

[Tetras]

Sorry, wrong link I pasted. I meant THIS one.

Yep, that looks better! You won't need the heatsink, but it is not important.

 

[Ravenholm]

I know but it is the only full black that I find and looks nice so lets go with that one. Many thanks. You saved me a lot of grief

 

[Tetras]

I know but it is the only full black that I find and looks nice so lets go with that one. Many thanks. You saved me a lot of grief

Let us know when you've got it and if it works good.

 

[Ravenholm]

Of course.
Now I see this page from the manual, this combo would be: 2x NVMe on CPU PCI lanes + 2x NVMe on Chipset PCI lanes:



SATA drives are not planned so I guess that those 2x NVMe Gen3 and 4 over Chipset would not cause any bottlenecks or problems.

 

[Tetras]

Now I see this page from the manual, this combo would be: 2x NVMe on CPU PCI lanes + 2x NVMe on Chipset PCI lanes:

This arrangement is pretty much the norm for 4x slot X670/X670E boards

 

[Spudgun]

x670e Steel legend will do this - if you are happy with

GPU @ PCIe 5 x 16
NVME 1 @ PCIe 5
NVME 2-4 @ PCIe 4

As noted above, if you want to go for 2 gen 5 PCIe NVME plugged directly into the motherboard, it often comes with compromises somewhere else due to the number of lanes available and all manufacturers seem to have tackled this differently by allocating their PCIe lane resources to different components

 

[Ravenholm]

Thanks, but as I already said, cannot return X670E-E Strix since I bought it second hand. Can resold it but I do not wanna bother now, just waiting this Icy Box expansion card arrives wednesday-thursday.

 

[Ravenholm]

Let us know when you've got it and if it works good.

Arrived today. Here are the results:

1. 970 EVO Plus - in M.2 socket


2. 970 EVO Plus - in PCI slot via adapter


Performance is basically the same, 5 times I ran tests, and 5 times different results so that is OK. Only temperature is little higher by 10°C when in expansion card (I installed thermalpad and a heatsink).

GPU is happily running at x16 so all went well.



Thanks again.