Question How to install my SSD's to benefit from all PCI-E lanes

Jun 28, 2021
Hi everyone,

I'm currently expanding my storage with a number of SSD's and would like to get full PCI-E lanes to a much drives as possible while still leaving as much lanes for my Graphics card too.
I've already done some research but my situation is a little different and I need some help on what slots I should use for what devices :).

I currently have the motherboard with a Ryzen 3950x CPU.

I've also bought one PCI-E to NVME adapter:
I read somewhere that these adapters are "dumb" and should support PCI-E 4.0 as well as 3.0. This is the first thing I can't find a definitive answer to and would like confirmation on :).

First of all I have a Nvidia RTX 3080 (PCI-E 4.0 x16)

I want to plug in the following SSD's (where one of them should sit on the Akasa adapter):
Samsung 980 PRO 2tb (PCI-E 4.0) - System Drive (I still need to install this)
Samsung 980 PRO 1tb (PCI-E 4.0) - Fast storage drive
ADATA SX8200PNP 2tb (PCI-E 3.0) - Big storage
Samsung 960 PRO 1tb (PCI-E 3.0) - Old system Drive but will be cloned to 980 pro

Next to this I have an Asus 10gbit PCI-E card (PCI-E 3.0 x4)

Currently my setup is as follows with the 980 PRO 2tb still to be added:

This setup results my GPU having 16 lanes, my 2 PCI-E 3.0 NVME disks having 4 lanes each, my 10gbit ASUS card having 4 lanes and my last 980 PRO only having 2 lanes.
Which is already more then the 24 lanes??? So I'm confused on how this all works.

If I sum up the PCI-E lanes I want to have in my final setup (including the 2tb 980 pro):
PCI-E 4.0 lanes: 24 (16 (GPU) + 4 (980 pro) + 4 (980 pro))
PCI-E 3.0 lanes: 12 (4 (960 pro) + 4 (ADATA) + 4 10gbit ASUS)

What would make most sense on how to install all of this while limiting the amount of devices being bottlenecked by having too little PCI-E lanes.

Here's an empty schema to fill in :) :

Some ideas / questions:
  1. Would it be best to simply have the GPU at 8 lanes?
  2. What happens if I just install all SSD's, so the 2x 980 pro in the top 2 slots and the PCI-E 3.0 ssd's in the lower slots. Which devices will get what lanes?
  3. Is my 10gbit network card even getting the full PCI-E 3.0 x4 lanes?
  4. And maybe in addition to that, are any of the devices in my current setup even getting the full lanes they should? If I simply count up the 4.0 and 3.0 lanes I'm already above 24 lanes. Or does it automatically split 2x 4.0 lanes into 4x 3.0 lanes?
  5. Any other suggestions :)?
The reason I've placed the 10gbit card at the bottom and the Akasa riser at the top is because the Akasa riser is a lot lower thus hopefully blocking less airflow to the GPU.
Your mainboard's manual will detail assorted PCI-e 4.0/3.0 connection limits...

(Not sure if X570 can do both M.2 NVME slots at PCI-e 4.0? An installed adapter in a PCI-e slot might help)

It would be hard to fathom pondering it being better to have only half the lanes active to the GPU to allow more lanes elsewhere to storage unless tops cores on CrystalDiskMark are the goal...; otherwise, the .3 seconds difference on game load times, boot times, etc., are not really noticeable between a 980 EVO and a 970 EVO, for instance...
Jun 28, 2021
I've read from some posts on the internet that the 3080 only benefits very slightly from a x16 slot (maybe 1 or 2 fps). But I hope someone else can give me some more insights in this.